The demand for water use in Phoenix in 2003 hit a high of about 442 million gallons per day on June 27. Water use in the summer is normally distributed with a mean of 310 million gallons per day and a standard deviation of 45 million gallons per day. City reservoirs have a combined storage capacity of nearly 350 million gallons.
(a) What is the probability that a day requires more water than is stored in city reservoirs?
(b) What reservoir capacity is needed so that the probability that it is exceeded is 1%?
(c) What amount of water use is exceeded with 95% probability?

Answers

Answer 1

Using the normal distribution, it is found that:

a) There is a 0.1867 = 18.67% probability that a day requires more water than is stored in city reservoirs.

b) A capacity of 415 million gallons is needed.

c) An amount of 236 million gallons of water use is exceeded with 95% probability.

Normal Probability Distribution

The z-score of a measure X of a normally distributed variable with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex] is given by:

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

The z-score measures how many standard deviations the measure is above or below the mean. Looking at the z-score table, the p-value associated with this z-score is found, which is the percentile of X.

The mean and the standard deviation for this problem are given as follows:

[tex]\mu = 310, \sigma = 45[/tex]

For item a, the probability is one subtracted by the p-value of Z when X = 350, hence:

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

Z = (350 - 310)/45

Z = 0.89

Z = 0.89 has a p-value of 0.8133.

1 - 0.8133 = 0.1867.

There is a 0.1867 = 18.67% probability that a day requires more water than is stored in city reservoirs.

For item b, the capacity should be the 99th percentile, which is X when Z = 2.327, hence:

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

2.327 = (X - 310)/45

X - 310 = 45 x 2.327

X = 415. (rounded)

A capacity of 415 million gallons is needed.

For item c, the amount of water use is the 5th percentile, which is X when Z = -1.645, hence:

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

-1.645 = (X - 310)/45

X - 310 = -1.645 x 45

X = 236.

An amount of 236 million gallons of water use is exceeded with 95% probability.

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Related Questions

532÷46
Also give remainder

Answers

Answer:

11 with a remainder of 26

Step-by-step explanation:

Check out the attached photo

Sasha has 520cm of rope she uses 2m 72mm of the rope how many millimeters of rope does Sasha have left?

Answers

Accoding to the given statements;

Sasha have left 2480 mm of rope.

According to the given values;

Sasha has 520 cm of rope

She used 2m 72 mm of rope

So, 1 cm = 10mm

And 1m = 1000mm

So, 520 × 10 = 5200mm

2.72× 1000 = 2720mm

5200 - 2720 = 2480mm

Sasha have left 2480 mm of rope.

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Triangle PQR has vertices P (3,8), Q (-5, 7), and R (0, 2). What are the coordinates of the vertices of the image after a reflection in the y-axis?
A) P' (3,-8)
B) P (-3,8)
□C) Q' (5,7)
□D) Q' (5-7)
□E) R¹ (-2,0)
OF) R¹ (0,2)

Answers

Triangle PQR has vertices P (3,8), Q (-5, 7), and R (0, 2) then the coordinates of the vertices of the image after a reflection in the y-axis will be:

P'' (-3,-8)

P' (3,8)

Q'' (-5,7)

Q'' (-5,-7)

R'' (2,0)

R'' (0,2).

A reflection around the axis and is given by the following rule:

(x, y) ----> (-x, y)

Applying the rule to each vertices of the reflection y - axis we have:

A) P' (3,-8) ----> P'' (-3,-8)

B) P (-3,8)  ----> P' (3,8)

C) Q' (5,7)  ----> Q'' (-5,7)

D) Q' (5,-7)  ----> Q'' (-5,-7)

E) R¹ (-2,0) ----> R'' (2,0)

F) R¹ (0,2) ----> R'' (0,2)

Therefore,

Triangle PQR has vertices P (3,8), Q (-5, 7), and R (0, 2) then the coordinates of the vertices of the image after a reflection in the y-axis will be:

P'' (-3,-8)

P' (3,8)

Q'' (-5,7)

Q'' (-5,-7)

R'' (2,0)

R'' (0,2).

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Which rational number equals 0.5?
A. 1/50
B. 1/5
C. 5/10
D. 5/9

Answers

C
Why?
Because 5 divided by 10 = 0.5

Answer:

C. 5/10

Step-by-step explanation:

Using a calculator:

Divide each numerator by each denominator. The answer must be 0.5

A. 1/50 = 0.02

B. 1/5 = 0.2

C. 5/10 = 0.5

D. 5/9 = 0.555...

Answer: C. 5/10

Without a calculator.

0.5 as a fraction is 1/2. Notice the denominator, 2, is twice the numerator, 1.

The answer also must have a denominator that is twice the numerator.

A. 1/50      2 × 1 = 2, not 50

B. 1/5         2 × 1 = 2, not 5

C. 5/10      2 × 5 = 10; this is it.

D. 5/9       2 × 5 = 10, not 9

Answer: C. 5/10

A piece of wood is 7 1/4 feet long. How many 2-foot long pieces can Sue cut from the wood?
A. 1
B. 2
C. 3
D. 4

Answers

The answer would be C. 3

Answer:

7.25 feet/2 feet = 3.625 pieces so you can have 3 pieces of 2 feet each and 1 piece left over that is less than 2 feet.

An account is opened with an initial deposit of $1100 and earns 3.7% interest compounded monthly.

What will the account be worth in 15 years?

Round your answer to the nearest cent.

Answers

In 15 years, the account will be worth $1896 if the 3.7% interest is compounded monthly on initial deposit of $1100.

What is compound interest?

It is the addition of interest to the principal sum of a loan or deposit, or in other words, interest on principal plus interest.

Given Data

A =  [tex]P(1+\frac{r}{100} )^{t}[/tex]

P=$1100

r =3.7%

t = 15years

Substitute the values in formula, A = [tex]P(1+\frac{r}{100} )^{t}[/tex]

A= 1100(1+{3.7/100})¹⁵

A = 1100(1+0.037)¹⁵

A = 1100(1.037)¹⁵

A= 1100(1.724)

A= 1896.4

Round off to nearest cent - $1896

Hence, $1896 will the account be worth in 15 years

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Please help!!!!
The equation for the line parallel to the graph of y = 6x + -2 with the same y- intercept as the graph of y = 36x + 2 is written as y = mx + b. Determine the values of m and b. What is the value of m + b?​

Answers

The values of m and b are 6 and 2 respectively and the value of m + b is 8.

The slope intercept of the straight line is used to find the equation of the straight line. The slope intercept formula requires knowing the slope of the line and the point of intersection of the line with the y-axis. Consider a  line with slope "m" and y-intercept "b". The slope-intercept shape formula for a straight line with slopes 'm' and 'b' as y-intercept is given as y = mx + b.

It is given that the equation y = mx + b   ....(1) for the line parallel to the graph of  y = 6x + -2    ...(2) means that slope of the equation y = mx + b which is parallel to the graph y = 6x + -2  is same i. e on comparing equation (1) and (2) , we get m = 6

On the other hand , the equation y = mx + b has the same y- intercept as the graph of y = 36x + 2   .....(3)

On  comparing equation (1) and (3) , we get b = 2

Therefore , m + b = 6 + 2

                             = 8

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Convert the decimal 0.875 to a percent.

Question 1 options:


0.875%


8.75%


875%



87.5%

Answers

Answer: 87.5%

hope this helps! :)

Answer:

A

Step-by-step explanation: i just did the test

Round to the nearest whole number, if necessary.

Answers

16.5 is 30% of 55

1650/55 = 30

Jaspar deposits £2,500 into a savings account at 7% per annum compound interest.
How much does he have in his account after 2 years?

Answers

Jasper had 362.25 in his account after two years, per the given statement.

What exactly is compound interest?

The interest you earn upon interest is known as compound interest. This may be demonstrated with simple math: if you have $100 and that it earns 5% interest every year, you will have $105 at the end of the first year. You'll have $110.25 by the end of the second year.

According to the given data:

Given:

Jaspar deposits £2,500

interest rate = 7

Time = 2 year

Compound interest is interest calculated on the aggregate amount rather than the principle amount alone.

Amount = P(1+r/100)^n

=2500(1+7/100)²

=2500(100+7/100)²

= 2500(107/100)²

= 2862.25

C.I.= Amount - Principal

= 2862.25-2500

= 362.25

According to the given statement jasper have 362.25 in his account after 2 years.

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The price of one ounce of gold is approximately $1750 US dollars. If the exchange rate is $1 US dollar = $0.85 Euro, how much will gold cost in Euro per gram?

Answers

Step-by-step explanation:

mm/kyc-kbiy-rvk come.

Answer:

Step-by-step explanation: Gold will cost €2.06 per gram.

What is ratio in mathematics?

Answers

Answer:

Ratio is a comparison between 2 numbers.

Hope this helps :)

Evaluate −y when y=6.

Answers

Answer:

-6

Step-by-step explanation:

y=6

-y=-6

Each graph shows a relation. The first and second numbers of each ordered pair in the relation are members of the set of real numbers. In each case, find the domain and the range of the relation and determine whether the relation is a function.

Answers

Answer:

Domain: [-2, 2]Range: [-2, 2]Not a function

Step-by-step explanation:

The domain is the set of x values and the range is the set of y values.

For the relation to the function, each value of x must map onto no more than one value of y.

Answer:

Domain: -2≥x≥2

Range: -2≥x≥2

Not a function

Step-by-step explanation:

Jenny is recording the percentages she earned on each quiz in her math class. Here are her results for the last 7 quizzes. 78, 80, 86, 82, 78, 67, 81. Find the range of the data set.

Answers

Answer:19

Step-by-step explanation:

The range of a data set in statistics is the difference between the largest and the smallest values.

86-67=19

>Read and solve each problem.
1 Two machines in a car parts factory mold different parts that will eventually be put
together in an assembly plant. The first machine makes a part every 12 seconds, and
the second machine makes a part every 45 seconds. The quality control engineer
tests these parts each time they both come out of the machines at the same time.
How often does she test the parts? Show your work and express your answer
in minutes.

Answers

Using the least common factor, it is found that she tests the parts once every 3 minutes.

How to find the time it takes for periodic events to repeat at the same time?

To find the time that passes between the events happening at the same time, we need to find the least common multiple of the periods.

For this problem, the periods are of 12 seconds and 45 seconds. The least common factor is found factoring both terms by prime factors, as follows:

12 - 45|2

6 - 45|2

3 - 45|3

1 - 15|3

1 - 5|5

1

Hence:

lcf(12, 45) = 2² x 3² x 5 = 180 seconds = 3 minutes.

She tests the parts once every 3 minutes.

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On the basis of past experience, a contractor expects to find 4.5% Broken Brickson every truckload. If he orders 2000 and Briggs will he have enough to complete a job require a 1900 bricks?

Answers

Yes, Briggs will have enough to complete a job requiring 1900 bricks. Since he has 1910 bricks remaining and he needs only 1900 bricks to complete the work.

Given that On the basis of past experience, a contractor expects to find 4.5% Broken Brickson every truckload.

He orders 2000.

We need to see whether Briggs will have enough to complete a job requiring 1900 bricks.

How to find a percentage of a number?

Example:

- 20% of M

= 20/100 x M

= 1/5 x M

- 25% of M

= 25/100 x M

= 1/4 x M

Find 4.5% of 2000.

= 4.5% x 2000

= 4.5 / 100 x 2000

= 4.5 x 20

= 45 x 2

= 90

The remaining bricks are:

= 2000 - 90

=  1910

We see that Briggs will have enough to complete a job requiring 1900 bricks.

1910 > 1900.

Thus, Briggs will have enough to complete a job requiring 1900 bricks.

Since he has 1910 bricks remaining and he needs only 1900 bricks to complete the work.

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1 a) A restaurant is open 24 hours a day. The manager wants to divide the day into work shifts of equal length. The shifts w=should not overlap. All shifts durations should be a whole number of hours. Describe the different ways this can be done.



b) The manager turns on the restaurant's two neon signs at the same time. Both signs blink as they are turned o. One blinks every 9 seconds. The other sign blinks every 15 seconds. In how many seconds will they blink together again?

Answers

The possible answers for the restaurants are Three 8-hour shifts; four 6-hour shifts; six 4-hour shifts.

2. The seconds that they will blink together again is 45 seconds.

How to illustrate the information?

Here we have to determine the factors of 24 for the shifts i.e.  1, 2, 3, 4, 6, 8, 12, 24 .

A 1-hour shift does not make much sense; most employers will also not use a 2-hour or 3-hour shift.

Restaurants typically do not use 12-hour shifts either, and employers do not use 24-hour shifts either.

Since both signs blink as they are turned on and one blinks every 9 seconds. The other sign blinks every 15 seconds. The least common multiple is 45.

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50 points help show your work and I’m giving brainliest

Answers

The values of the expressions in the table following their evaluation are;

1. 73

2. 97

3. x = 108

4. -13/6

5. 1 and 97

6. 1 and 41

7. The graph of the number line

8. She needs to add 5/36 cup of sugar

The length of the actual is 6 miles

How can the expressions be evaluated?

1. The given expression is 5•x + 14 - 6

The value of x at which the expression is evaluated is x = 13

Which gives;

5×13 + 14 - 6 = 73

2. Twelve times six plus 25 can be expressed as 12 × 6 + 25

12 × 6 + 25 = 97

3. x/9 = 12

Multiplying across gives;

x × 1 = 9 × 12 = 108

x = 108

4. The expression is 3/16 - 3/8

= (3 - 2× 3)/16

3/16 - 3/8 = (3 - 2× 3)/16 = -3/16

(3 - 2× 3)/16 = -3/16

5. The prime factors of 97 are; 1 and 97

6. 41 is a prime number.

The factors of 41 are; 1 and 41

7. The graph of x = -1/3

8. Quantity of sugar required = 3¼

Quantity added = 3⅑

Quantity needed = 3¼ - 3⅑ = 5/36

9. 4 inches is equivalent to 2 miles

Therefore;

12 inches = 3 × 4 inches is equivalent to 3 × 2 mi = 6 mi

The length of the actual trail is 6 miles

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2. What answer represents this number in scientific notation? (
0.00000916
0916 x 10-8
09.16 x 10-6
0916 x 108
09.16 x 106
HELP PLS HURRY

Answers

Answer:

9.16 × 10-6

Step-by-step explanation:

Evaluate 2^3x-1 for x = 1.

Answers

Answer:4

Step-by-step explanation:

2 to the power of 3x-1 when x=1

Replace x with 1 for 3(1)-1=2

2 to the power of 2 is 2*2 which equals 4

Alternatively if the question means 2 to the power of 3x minus 1

Replace x with 1 for 3(1)=3

2 to the power of 3 is 2*2*2 which equals 8

8-1=7

what are the answers for the table

Answers

Answer:
X-intercepts: -1 and 3

Y-intercepts: 3
Vertex: (1, 4)
Axis of Symmetry: y= -1x + 3x + 4 (I think this is right it might not be and im sorry if it isnt).

Step-by-step explanation: Hope this helps even a little bit <33

The diameter of Jupiter at its equator is approximately 1.43 x 10 to the 5th power kilometers. Write this number in standard notation. An astronomer's infrared telescope is able to detect radiation with a wavelength of 0.000439 meters. Write this number in scientific notation.

Answers

The number in standard notation is 143,000.

The number in scientific notation is 4.39 x 10^-4

What is scientific and standard notation?

Scientific notation is used to compress large numbers into smaller numbers. In order to write a number in scientific notation, the number is written as a decimal number, between 1 and 10 and multiplied by a power of 10.

For example:

• The number : 1 x 10² is equivalent to 100

• The number 5 x 10³ is equivalent to 500

When changing a number that is less than 1 to scientific notation, there would be a negative sign before the power.

0.000439 = 4.39 x 10^-4

In order to convert a number from scientific notation to standard notation, multiply the number by its power.

1.43 x 10^5

= 1.43 x 100,000 = 143,000

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Step by step how do I
Estimate. Then record the product. 608 x 6=

Answers

Answer:

Estimated answer = 3,000

Product/Answer = 3,648

Hope this helps :)

Explanation below.

Step-by-step explanation:

1. To estimate, firat round the two numbers, 608 and 6.

When rounding if the numbers are 1,2,3,4 round down and if the numbers are 5,6,7,8,9 round up. But in this case we are just estimating an answer so we can just round 6 to 5 and 608 to 600. However, if the directions say to round to a specific place value, then follow the directions.

608 rounded to 600

6 rounded to 5

2. Multiply.

600 × 5 = 3,000

3. Solve with exact given numbers.

608 × 6 = 3,648

AB=20
A and B are integers; they may or may not be distinct.
Which of the following could be equal to A-B?
A. 9
B.7
C.6
D.8
Please show me how you figured this out.

Answers

How you figure it out is you do 17+3

Select the correct answer. Find the inverse of function f. 1/2x+7

Answers

Answer: y=2x-14

Step-by-step explanation:

Solve for x

x/2+7 = y

x/2+7-7=y-7

x/2=y-7

2x/2=2(y-7)

x=2y-14

y=2x-14  ==> switch the x and y variables

The top numbers for 8 and 20

Answers

Answer:

Step-by-step explanation:

2/4 is equal to 0.5

4/8 is equal to 0.5

10/20 is equal to 0.5

A frequency table of grades has five classes A B C D F with frequencies of 4,11,14,5 and 3 using percentages what are the relative frequencies

Answers

Answer:

A frequency table of grades has five classes A B C D F

Step-by-step explanation:

A frequency table of grades has five classes A B C D F

Which step is not necessary when solving this system of equations by graphing?
3x-y-4
X+y=-4
O
Identify the point of intersection
O Choose a method to graph the equations.
O Determine the shaded area for each line.
O Write the solution as an ordered pair

Answers

Step (B) determining the shaded area for each line is not required when graphing this system of equations.

What do we mean by equations?In its most basic form, an equation is a mathematical statement that shows that two mathematical expressions are equal. 3x + 5 = 14, for example, is an equation in which 3x + 5 and 14 are two expressions separated by a 'equal' sign.When solving this system of equations by graphing, it is not necessary to determine the shaded area for each line.

As it is given in the description itself, when solving this system of equations by graphing, it is not necessary to determine the shaded area for each line.

Therefore, step (B) determining the shaded area for each line is not necessary when solving this system of equations by graphing

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The correct question is given below:
Which step is not necessary when solving this system of equations by graphing?

3x-y-4

X+y=-4

O

Identify the point of intersection

(A) Choose a method to graph the equations.

(B) Determine the shaded area for each line.

(C) Write the solution as an ordered pair

What is the range of possible sizes for side x? (Khan)

Answers

The range of possible sizes for side x is 2.3 < x < 8.7.

What are the possible sizes for the missing side of a triangle?

Herein we have a triangle, of which two of its sides are known and we can now the set of all possible values by using the law of the cosine:

x² = 3.2² + 5.5² - 2 · 3.2 · 5.5 · cos θ

x = √(40.49 - 35.2 · cos θ)

The cosine is bounded between - 1 and 1, then the possible sizes for the side x are:

2.3 < x < 8.7

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