Answer: circumference of the circle is 11.31 meters
C=\pi d\\C=\pi (2r)\\C=2\pi r
Where radius (r) is half of diameter (d)
Since radius of the circle shown in 1.8m, we plug it in the formula and get:
C=2\pi r\\C=2\pi (1.8)\\C=11.31
So C = 11.31 meters
A gumball machine has 100 red gumballs. If the red gumballs are 25% of the total number of gumballs, how many gumballs are in the gumball machine?
Answer: 400
Step-by-step explanation:
25% is equal to one quarter (1/4). If theres 100 red gumballs then there must be 300 more gumballs in the machine because a quarter of a number is always even.
Devon wants to build a ramp with the dimensions shown. How much wood does he need?
The image of the ramp with dimensions is missing, so i have attached it.
Answer:
680 in² of wood is needed.
Step-by-step explanation:
The way to find how much wood would be needed by devon would be to find the total surface area of the ramp.
From the attached image,
Let's find the area of the 2 triangles first;
A1 = 2(½bh) = bh = 15 x 8 = 120 in²
Area of the slant rectangular portion;
A2 = 17 x 14 = 238 in²
Area of the base;
A3 = 15 × 14 = 210 in²
Area of vertical rectangle;
A4 = 8 × 14 = 112 in²
Total Surface Area = A1 + A2 + A3 + A4 = 120 + 238 + 210 + 112 = 680 in²
Help Me PLEASE!!!
A card is chosen at random from a standard deck of 52 cards, and then it is replaced and another card is chosen. What is the probability that at least one of the cards is a diamond or an ace?
Answer:
P = 0.5207
Step-by-step explanation:
First, we have three options: Just the first card is a diamond or an ace, Just the second card is a diamond or an ace and both cards are diamonds or aces.
Additionally, there are 16 cards that are diamond or aces in a standard deck of 52 cards (13 diamonds and 3 aces that are not diamonds). It means that there are 36 cards that are not diamond or aces (52 - 16 = 36).
So, the probability that just the first card is a diamond or an ace is calculated as:
[tex]P_1=\frac{16}{52}*\frac{36}{52}=0.2130[/tex]
At the same way, the probability that just the second card is a diamond or an ace is:
[tex]P_2=\frac{36}{52}*\frac{16}{52}=0.2130[/tex]
Finally, the probability that both cards are diamonds or aces is:
[tex]P_3=\frac{16}{52}*\frac{16}{52}=0.0947[/tex]
Therefore, the probability that at least one of the cards is a diamond or an ace is:
[tex]P=P_1+P_2+P_3\\P=0.2130+0.2130+0.0947\\P=0.5207[/tex]
A hotel with 95 room has 65 for doubles and 25 for singles. Singles can be booked in any room, but reservations for two or more people must be booked in double rooms. Let x be the number for single reservations and y the reservations for two or more. Which system of inequality represents this situation? Click the correct answer y is greater than or equal to 65 x+y less than or equal to 95 y is less than or equal to 65 x+y less than or equal to 95 x is greater than or equal to 25 x+y less than or equal to 95 x is less than or equal to 25 x+y less than or equal to 95
Answer: Y is less than or equal to 65 and X + y= less than or equal to 95
Write the equation of the line shown in the graph above in slope-intercept form. Question 3 options: A) y = –2∕3x + 1 B) y = –x + 2∕3 C) 2x + 3y = 3 D) y = 2∕3x + 1
Answer:
A) y = -2/3x + 1
Step-by-step explanation:
Slope - intercept form is y = mx + b, where m is the slope and b is the y - intercept.
The line is falling from left to right, so it has a negative slope.
y = -mx + b
The line has a slope of -2/3.
y = -2/3x + b
The line has a y - intercept of 1.
y = -2/3x + 1
I hope this helps :)
A) y = -2/3x + 1, the equation of the line shown in the graph above in slope-intercept form.
What is a straight line?A straight line is an endless one-dimensional figure that has no width. It is a combination of endless points joined both sides of a point and has no curve.
here, we have,
Slope - intercept form is y = mx + b,
where m is the slope and b is the y - intercept.
The line is falling from left to right, so it has a negative slope.
y = -mx + b
As, the line passes through (0,1) and (1.5,0)
The line has a slope of -2/3.
y = -2/3x + b
The line has a y - intercept of 1.
y = -2/3x + 1
hence, A) y = -2/3x + 1, the equation of the line shown in the graph above in slope-intercept form.
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please help me explain your answer only answer if you are sure
Answer:
The answer of top prism is 262
and down prism is 478
The upper figure is triangular prism.
so, we use bh+2ls+lb formula
B=5
h=3
s=4
l=19
Now,
surface area of triangular prism = bh+2ls+lb
= 5×3+2×19×4+19×5
= 262
The down figure is rectangular prism.
so, we use 2lw+2lh+2hw
l=5
h=6
w=19
Now,
The area of rectangular prism = 2lw+2lh+2hw
= 2×5×19+2×19×6+2×5×6
= 478
Kimberly goes on a road trip; her car gets 25 miles per gallon (mpg) and gas costs $3.24 per gallon. Let n represent the number of miles Kimberly has traveled since she started driving.
a. Suppose Kimberly has traveled 252 miles (n 252) since she started driving. i. How many gallons of gasoline has she used since she started driving? gallons Preview i. What is the cost of the gasoline that she has used since she started driving?
b. Write an expression in terms of n that represents the number of gallons of gasoline she has used since she started driving.
c. Write an expression in terms of n that represents the cost of the gasoline that she has used since she started driving.
Answer:
a) 10.08 gallons and $32.66 of gas
b) gallons used = n/25
c)cost of the gasoline = [tex]\frac{n}{25}(3.24)[/tex]
Step-by-step explanation:
a) We know that Kimberly has traveled 252 miles and we also know that her car gets 25 miles per gallon. We can apply proportions and rule of three:
25 miles ------ 1 gallon
252 miles ----- x gallons
Solving for x:
x gallons = 252 miles(1 gallon)/25 miles= 10.08 gallons.
Thus, she has used 10.08 gallons since she started driving.
Now we need to know the cost of the gasoline that she has used.
We know that each gallon of gas costs $3.24 and she has used 10.08 gallons. Again, we can apply proportions and rule of three:
1 gallon ------ 3.24 dollars
10.08 gallons---- x dollars.
Solving for x we get:
[tex]x=(10.08)(3.24)[/tex]= 32.659=32.66 dollars.
Thus, she has used $32.66 of gas since she started driving.
b) Write an expression in terms of n that represents the number of gallons of gasoline she has used since she started driving.
If we know that n is the number of miles that she drives, from what we wrote above, an expression to know the number of gallons she has used would be:
Gallons used = n/25 (since her car gets 25 miles per gallon) where n is the number of miles.
c) Write an expression in terms of n that represents the cost of the gasoline that she has used since she started driving.
Again, to know the cost of the gasoline we first need to know how many gallons she has used. From b) we know that the expression to know how many gallons she has used is n/25. Since each gallon costs $3.24 we will multiply this number by n/25 and we will get the cost (like we did in a))
Therefore, the cost of the gasoline = [tex]\frac{n}{25}(3.24)[/tex] where n is the number of miles.
An oval shaped walking path at a local park is 3/4 of a mile long. Four walkers recorded the number of laps they walked and the time it took them in them.
laps Minutes
Amber. 3. 40. Bruno. 4. 54. Cady. 5. 75. Drake. 6. 72.
Match each walker to their corresponding unit rate in miles per hour................................................. 3 3/4 mph, 3 mph, 3 1/2mph, 3 1/4 mph, 3 3/8 mph and 3 2/3mph
Answer:
Amber = 3 3/8 mphBruno = 3 1/3 mphCady =3 mphDrake = 3 3/4 mphStep-by-step explanation:
Consider the calculations in the table below with the respective columns being: Name | Laps | Time | Time(in hours) |Total Distance | Unit Rate
[tex]\left|\begin{array}{c|c|c|c|c|c}---&---&---&----&----&---\\Amber&3&40&\frac{40}{60}&3*\frac{3}{4}=2.25&2.25 \div \frac{40}{60}= 3\frac{3}{8} \\\\Bruno&4&54&\frac{54}{60}&4*\frac{3}{4}=3&3 \div \frac{54}{60}= 3\frac{1}{3}\\\\Cady&5&75&\frac{75}{60}&5*\frac{3}{4}=3.75&3.75 \div \frac{75}{60}= 3 \\\\Drake&6&72&\frac{72}{60}&6*\frac{3}{4}=4.5&4.5 \div \frac{72}{60}= 3\frac{3}{4} \end{array}\right|[/tex]
We can then match each walker to their respective unit rates in miles per hour.
Amber = 3 3/8 mphBruno = 3 1/3 mphCady =3 mphDrake = 3 3/4 mph2. En la ciudad de Quito, en la temporada fría, se registran temperaturas que van desde los 5 °C hasta los 18 °C. En la temporada cálida, el registro de la temperatura va desde los 4 °C hasta los 30 °C.
a. Representamos estas temperaturas en forma de intervalo y como conjunto.
b. ¿A qué intervalo pertenece la temperatura de la ciudad de Quito?
c. ¿Qué temperaturas son comunes en las temporadas fría y cálida?
d. ¿Qué temperaturas son posibles solo en la temporada fría?
e. ¿Qué temperaturas son posibles solo en la temporada cálida?
Answer:
(See explanation below for further detail/Véase la explicación abajo para mayores detalles)
Step-by-step explanation:
(This exercise is written in Spanish and explanations will be held in such language)
a) Las temperaturas quedan representadas a continuación:
Quito - Temporada Fría
Intervalo
[tex]5 ^{\circ}C \leq t \leq 18^{\circ}C[/tex] (Este intervalo indica si el dato puede pertenecer a la temporada fría)
Conjunto
[tex]C = \{\forall t \in \mathbb {R}| 5 \leq t \leq 18\}[/tex] (Este conjunto acumula todo el registro de las temperaturas de la temporada fría)
Quito - Temporada Cálida
Intervalo
[tex]4 ^{\circ}C \leq t \leq 30^{\circ}C[/tex] (Este intervalo indica si el dato puede pertenecer a la temporada cálida)
Conjunto
[tex]H = \{\forall t \in \mathbb {R}| 4 \leq t \leq 30\}[/tex] (Este conjunto acumula todo el registro de las temperaturas de la temporada cálida)
b) La temperatura de la ciudad de Quito pertenece esencialmente a dos intervalos:
Intervalo de Temporada Fría:
[tex]5 ^{\circ}C \leq t \leq 18^{\circ}C[/tex]
Intervalo de Temporada Cálida:
[tex]4 ^{\circ}C \leq t \leq 30^{\circ}C[/tex]
c) Toda temperatura mayor o igual que 4 °C y menor o igual que 30 °C.
d) Temperaturas mayores o iguales a 5 °C y menores o iguales a 18 °C.
e) Temperaturas mayores o iguales a 4 °C y menores o iguales a 30 °C.
Fifty random shoppers at an electronics store have been interviewed and 35 of them intend to purchase a newly released smart phone. What probability distribution describes this situation and what are its mean and standard deviation of phone sales if we are concerned about 1071 shoppers that day
Answer:
We use the binomial distribution to describe this situation.
The mean number of phone sales is 749.7 with a standard deviation of 15.
Step-by-step explanation:
For each shopper, there are only two possible outcomes. Either they plan to purchase the newly released smart phone, or they do not. Each customer is independent of other customers. So we use the binomial distribution to solve this question.
Binomial probability distribution
Probability of exactly x sucesses on n repeated trials, with p probability.
The expected value of the binomial distribution is:
[tex]E(X) = np[/tex]
The standard deviation of the binomial distribution is:
[tex]\sqrt{V(X)} = \sqrt{np(1-p)}[/tex]
Fifty random shoppers at an electronics store have been interviewed and 35 of them intend to purchase a newly released smart phone.
This means that [tex]p = \frac{35}{50} = 0.7[/tex]
What are its mean and standard deviation of phone sales if we are concerned about 1071 shoppers that day
1071 shoppers, so [tex]n = 1071[/tex]
Mean
[tex]E(X) = 1071*0.7 = 749.7[/tex]
Standard deviation
[tex]\sqrt{V(X)} = \sqrt{1071*0.7*0.3} = 15[/tex]
The mean number of phone sales is 749.7 with a standard deviation of 15.
From the top of the cliff 8m high,two boats are seen in the direction due west.find the distance between the boats if the angles of depression from the top of the cliff are 45° and 30°.Find also the actual distance of the farther boat from the top of the cliff.
Answer:
Distance between 2 boats= 5.86m (3 s.f.)
Actual distance from farther boat from top of cliff= 16m
Step-by-step explanation:
Please see the attached pictures for full solution.
25
Which expression represents half the sum of n and 7 ?
Answer:
1/2(n+7)
the sum of n and 7 is (n+7). to half it just put 1/2 in front of the parentheses. :)
Please answer this correctly
Answer:
326
Step-by-step explanation:
l x w
7x8
25x6
4x30
326
Henry, Brian and Colin share some sweets in the ratio 6:4:1. Henry gets 25 more sweets than Colin. How many sweets are there altogether?
Answer:
There are 55 sweets in total.
Step-by-step explanation:
The total number of sweets is t.
Henry, Brian and Colin share some sweets in the ratio 6:4:1.
This means that Henry earns [tex]\frac{6}{6+4+1} = \frac{6}{11}[/tex] of the total(t).
Brian earns [tex]\frac{4}{11}[/tex] of the total.
Colin earns [tex]\frac{1}{11}[/tex] of the total
Henry gets 25 more sweets than Colin.
Henry earns [tex]\frac{6t}{11}[/tex]
Colin earns [tex]\frac{t}{11}[/tex]
So
[tex]\frac{6t}{11} = \frac{t}{11} + 25[/tex]
Multiplying everything by 1
[tex]6t = t + 275[/tex]
[tex]5t = 275[/tex]
[tex]t = \frac{275}{5}[/tex]
[tex]t = 55[/tex]
There are 55 sweets in total.
How do u solve this?
Answer:
0
Step-by-step explanation:
Tuesday : -1/2
Wednesday + 3/4
Thursday : -3/8
Add them together
-1/2 + 3/4- 3/8
Get a common denominator
-4/8 + 6/8 - 3/8
-1/8
The closest integer value to -1/8 is 0
A soccer field is a rectangle 30 meters wide and 120 meters long.The coach asks players to run from one corner to the corner diagonally across. What is the distance to the nearest tenth of a mile
Answer:
123.7 meters
Step-by-step explanation:
If you draw a diagram, this will be a rectangle and the line across cuts it into a right triangle, with a base of 120 and a height of 30. The need to know the length of the hypotenuse of the triangle, so we can use the pythagorean theorem.
30^2 + 120^2 = c^2
c=123.7
Two positive numbers have a difference of 8. The larger number is three more than twice the smaller. Find the two numbers.
Answer:
5 and 13
Step-by-step explanation:
Let x represent the smaller number. Then the larger number is 2x+3, and the difference is ...
(2x+3) -(x) = 8
x = 5
The two numbers are 5 and 13.
_____
Check
Twice the smaller number is 10. 3 more than that is 13, the larger number. Their difference is 13 -5 = 8.
Mr Chan flies from London to Los Angeles, a distance of 8800 km.
The flight takes 11 hours and 10 minutes.
His plane leaves London at 09 35 local time.
The local time in Los Angeles is 8 hours behind the time in London.
Calculate the local time when the plane arrives in Los Angeles.
Answer:
12 45
Step-by-step explanation:
plane leaves London at 09 35
plane arrives in Los Angeles after 11 hrs and 10 min
considering time difference:
11 10 - 8 00= 03 10local arrival time:
09 35 + 03 10= 12 45 local time36°
I
80°
w
m
What equation can be used to calculate the measure of angle ? Describe, in words, the
process you would use to find
Answer:
44°
Step-by-step explanation:
A pair of angles formed from the intersection of two lines opposite to each other at the point of intersection (vertex) is called vertically opposite angles. These vertically opposite angles are congruent to each other (that means they are equal).
Since opposite angles are equal, the equation needed to calculate w is given as:
80° = 36° + w
w = 80° - 36°
w = 44°
Look at the work shown for the division problem shown on the right. The remainder is 8 . Now, evaluate f (x) = 2x4 – 4x3 – 11x2 + 3x – 6 for x = –2. f (–2) = 8 Compare the values you entered above. f (–2) is the remainder when dividing the polynomial by x + 2. Divide 2x4- 4x3 - 11x2 + 3x - 6 by x + 2.
Answer:
1st : 8
2nd: 8
3rd: equal to
Polynomial is an equation written as the sum of terms of the form kx^n.
where k and n are positive integers.
The remainder of the polynomial when divided by x + 2 is -60.
What is a polynomial?Polynomial is an equation written as the sum of terms of the form kx^n.
where k and n are positive integers.
We have,
2[tex]x^{4}[/tex] - 4x³ - 11x² + 3x - 6 divide by x + 2.
Now,
x + 3 ) 2[tex]x^{4}[/tex] - 4x³ - 11x² + 3x - 6 ( 2x³ - 2x² - 5x + 18
2[tex]x^{4}[/tex] + 6x³
(-) (-)
-2x³ - 11x² + 3x - 6
-2x³ - 6x²
(+) (+)
- 5x² + 3x - 6
-5x² - 15x
(+) (+)
18x - 6
18x + 54
(-) (-)
-60
We see that,
The remainder is -60.
f(-2) = 2[tex]x^{4}[/tex] - 4x³ - 11x² + 3x - 6
f(-2) = 2 x 16 + 32 - 44 - 6 - 6 = 32 + 32 - 44 - 12 = 64 - 56 = 8
Thus,
The remainder of the polynomial when divided by x + 2 is -60.
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Watermelon A is 2 kg lighter than watermelon B and it weighs one fifth of the weight of watermelon C. Watermelons A and C together are 3 times as heavy as watermelon B. How heavy is each watermelon?
Answer:
A: 2 kgB: 4 kgC: 10 kgStep-by-step explanation:
We can write some equations to describe the given relationships:
A = B - 2 . . . . . A is 2 kg lighter than B
A = C/5 . . . . . . A is 1/5 the weight of C
A+C = 3B . . . . together, A and C are 3 times the weight of B
__
Let's solve for A.
B = A+2 . . . from the first equation
C = 5A . . . . from the second equation
A +5A = 3(A+2) . . . . substituting for B and C in the third equation
6A = 3A +6
3A = 6
A = 2
__
B = A+2 = 4
C = 5A = 10
Watermelon A weighs 2 kg; B weighs 4 kg; and C weighs 10 kg.
Answer:
2 kg 4 kg 10 kg
I BLESS THE EYES!
Assume that random guesses are made for seven multiple choice questions on an SAT test, so that there are n=7 trials, each with probability of success (correct) given by p= 0.2. Find the indicated probability for the number of correct answers.
Find the probability that the number x of correct answers is fewer than 4.
Answer:
Step-by-step explanation:
Let x be a random variable representing the number of guesses made for the sat questions.
Since the probability of getting the correct answer to a question is fixed for any number of trials and the outcome is either getting it correctly or not, then it is a binomial distribution. The probability of success, p = 0.2
Probability of failure, q = 1 - p = 1 - 0.2 = 0.8
the probability that the number x of correct answers is fewer than 4 is expressed as
P(x < 4)
From the binomial distribution calculator,
P(x < 4) = 0.97
Temperature transducers of certain type are shipped in batches of 50. A sample of 60 batches was selected, and the number of transducers in each batch not conforming to design specifications was determined, resulting in the following data:
2 1 2 3 1 1 3 2 0 5 3 3 1 3 2 4 7 0 2 3
0 4 2 1 3 1 1 3 41 2 3 2 2 8 4 5 1 3 1
5 0 2 3 2 1 0 6 4 2 1 6 0 3 3 3 6 2 3
a. Determine frequencies and relative frequencies for the observed values of x = number of non-conforming transducers in a batch. (Round your relative frequencies to three decimal places.)
b. What proportion of batches in the sample have at most four non-conforming transducers? (Round your answer to three decimal places.)
Answer:
a.
Number: 0, 1, 2, 3, 4, 5, 6, 7, 8
Frequency: 6, 12, 13, 15, 5, 3, 3, 1, 1
b. The proportion of the batches that have at most is 0.864
Step-by-step explanation:
a. The given data are;
2 1 2 3 1 1 3 2 0 5 3 3 1 3 2 4 7 0 2 3
0 4 2 1 3 1 1 3 4 1 2 3 2 2 8 4 5 1 3 1
5 0 2 3 2 1 0 6 4 2 1 6 0 3 3 3 6 2 3
The frequencies are;
x fx
0 6
1 12
2 13
3 15
4 5
5 3
6 3
7 1
8 1
The relative frequency are;
x Rfx
0 0.102
1 0.203
2 0.220
3 0.254
4 0.085
5 0.051
6 0.051
7 0.017
8 0.017
b. The proportion of the batches that have at most 4 is given as follows;
The number of the batches that have at most 4 = 6 + 12 + 13 + 15 + 5 = 51
Therefore, the proportion of the batches that have at most 4 = 51 / 59 = 0.864.
Given F1 = ∑ m(0,2,5,7,9) and F1 = ∑ m(2, 3,4,7,8) find the minterm expression for F1+F2. State a general rule for finding the expression for F1+F2 given the minterm expansions for F1 and F2. Prove your answer by using the general form of the minterm expansion.
Answer:
Step-by-step explanation:
The question tells us that;
Given F1 = ∑ m(0,2,5,7,9) and F1 = ∑ m(2, 3,4,7,8) find the minterm expression for F1+F2. State a general rule for finding the expression for F1+F2 given the minterm expansions for F1 and F2. Prove your answer by using the general form of the minterm expansion.
Note: The answer is provided in the image uploaded below
cheers i hope this helped !!!
Solve the problem.
If a boat uses 25 gallons of gas to go 73 miles, how many miles
can the boat travel on 75 gallons of gas?
24 mi
438 mi
219 mi
239 mi
Answer:
For this problem we can use the following proportional rule:
[tex] \frac{73 mi}{25 gal}= \frac{x}{75 gal}[/tex]
Where x represent the number of miles that we can travel with 75 gallons. For this case we can use this proportional rule since by definition [tex] D=vt[/tex]. If we solve for x we got:
[tex] x =75 gal (\frac{73 mi}{25 gal}) =219mi[/tex]
And the best answer would be:
219 mi
Step-by-step explanation:
For this problem we can use the following proportional rule:
[tex] \frac{73 mi}{25 gal}= \frac{x}{75 gal}[/tex]
Where x represent the number of miles that we can travel with 75 gallons. For this case we can use this proportional rule since by definition [tex] D=vt[/tex]. If we solve for x we got:
[tex] x =75 gal (\frac{73 mi}{25 gal}) =219mi[/tex]
And the best answer would be:
219 mi
A bag contains 1p,20 and 5p coins 3/8 of the bag are 1p coins There are as many 5p coins as 1p coins in the bag. There are 640 coins in total. Work out the number of 20 coins in the bag
Answer:
160 off 20p coins
Step-by-step explanation:
1 p, 20 p, 5 p coins1 p= 3/8 of the bag5 p= 1 p= 3/8 of the bagtotal coins= 64020 p coins= 640 - 640*(3/8+3/8)= 640*(1- 6/8)= 640 * 2/8= 640* 1/4= 160
Please help me i need the answer if i knew it i will complete all of them by my self (: .
The right answer is 100 units^2
please see the attached picture for full solution
Hope it helps
Good luck on your assignment,
The percent, X , of shrinkage o n drying for a certain type of plastic clay has an average shrinkage percentage :, where parameter : is unknown. A random sample of 45 specimens from this clay showed an average shrinking percentage of 18.4 and a standard deviation of 2.2.
Required:
a. Estimate at 5% level of significance whether the true average shrinkage percentage U: is greater than 17.5 and write your conclusion.
b. Report the p-value.
Answer:
a) [tex]t=\frac{18.4-17.5}{\frac{2.2}{\sqrt{45}}}=2.744[/tex]
The degrees of freedom are given by:
[tex]df=n-1=45-1=44[/tex]
The critical value for this case is [tex]t_{\alpha}=1.68[/tex] since the calculated value is higher than the critical we have enough evidence to reject the null hypothesis and we can conclude that the true mean is significantly higher than 18.4
b) [tex]p_v =P(t_{(44)}>2.744)=0.0044[/tex]
Step-by-step explanation:
Information given
[tex]\bar X=18.4[/tex] represent the sample mean
[tex]s=2.2[/tex] represent the sample standard deviation
[tex]n=45[/tex] sample size
[tex]\mu_o =17.5[/tex] represent the value to verify
[tex]\alpha=0.05[/tex] represent the significance level
t would represent the statistic
[tex]p_v[/tex] represent the p value
Part a
We want to test if the true mean is higher than 17.5, the system of hypothesis would be:
Null hypothesis:[tex]\mu \leq 17.5[/tex]
Alternative hypothesis:[tex]\mu > 17.5[/tex]
The statistic is given by:
[tex]t=\frac{\bar X-\mu_o}{\frac{s}{\sqrt{n}}}[/tex] (1)
And replacing we got:
[tex]t=\frac{18.4-17.5}{\frac{2.2}{\sqrt{45}}}=2.744[/tex]
The degrees of freedom are given by:
[tex]df=n-1=45-1=44[/tex]
The critical value for this case is [tex]t_{\alpha}=1.68[/tex] since the calculated value is higher than the critical we have enough evidence to reject the null hypothesis and we can conclude that the true mean is significantly higher than 18.4
Part b
The p value would be given by:
[tex]p_v =P(t_{(44)}>2.744)=0.0044[/tex]
The differential equation below models the temperature of a 91°C cup of coffee in a 17°C room, where it is known that the coffee cools at a rate of 1°C per minute when its temperature is 70°C. Solve the differential equation to find an expression for the temperature of the coffee at time t. dy dt = − 1 53 (y − 17)\
Answer:
[tex]t \approx 17.690\,min[/tex]
Step-by-step explanation:
This differential equation is a first order linear differential equation with separable variables, whose solution is found as follows:
[tex]\frac{dy}{dt} = - \frac{1}{53} \cdot (y - 17)[/tex]
[tex]\frac{dy}{y-17} = -\frac{1}{53} \, dt[/tex]
[tex]\int\limits^{y}_{y_{o}} {\frac{dy}{y-17} } = -\frac{1}{53} \int\limits^{t}_{0}\, dx[/tex]
[tex]\ln \left |\frac{y-17}{y_{o}-17} \right | = -\frac{1}{53} \cdot t[/tex]
[tex]\frac{y-17}{y_{o}-17} = e^{-\frac{1}{53}\cdot t }[/tex]
[tex]y = 17 + (y_{o} - 17) \cdot e^{-\frac{1}{53}\cdot t }[/tex]
The solution of the differential equation is:
[tex]y = 17 + 74\cdot e^{-\frac{1}{53}\cdot t }[/tex]
Where:
[tex]y[/tex] - Temperature, measured in °C.
[tex]t[/tex] - Time, measured in minutes.
The time when the cup of coffee has the temperature of 70 °C is:
[tex]70 = 17 + 74 \cdot e^{-\frac{1}{53}\cdot t }[/tex]
[tex]53 = 74 \cdot e^{-\frac{1}{53}\cdot t }[/tex]
[tex]\frac{53}{74} = e^{-\frac{1}{53}\cdot t }[/tex]
[tex]\ln \frac{53}{74} = -\frac{1}{53}\cdot t[/tex]
[tex]t = - 53\cdot \ln \frac{53}{74}[/tex]
[tex]t \approx 17.690\,min[/tex]
Seventy-six percent of sunflower seeds will germinate into a flower, and a sample of 800 such sunflower seeds is randomly selected. The standard deviation for the number of sunflower seeds that will germinate in such samples of size 800 is:
Answer:
12.08
Step-by-step explanation:
For each sunflower, there are only two possible outcomes. Either it germinates, or it does not. The probability of a sunflower germinating is independent of other sunflowers. So we use the binomial probability distribution to solve this question.
Binomial probability distribution
Probability of exactly x sucesses on n repeated trials, with p probability.
The standard deviation of the binomial distribution is:
[tex]\sqrt{V(X)} = \sqrt{np(1-p)}[/tex]
Seventy-six percent of sunflower seeds will germinate into a flower
This means that [tex]p = 0.76[/tex]
Samples of 800:
This means that [tex]n = 800[/tex]
The standard deviation for the number of sunflower seeds that will germinate in such samples of size 800 is:
[tex]\sqrt{V(X)} = \sqrt{np(1-p)} = \sqrt{800*0.76*0.24} = 12.08[/tex]
