URGENT PLS HELP. pls but why or why not thank you:))

Answer:

160 chemistry books and 80 history books

Step-by-step explanation:

C=chemistry books sold, H=history books sold

C=2H

C+H=240, 3H=240, H=80, C=160

Answer:

(2,1)

Step-by-step explanation:

2x - 2y = 2

5x + 2y = 12

again just add them in this case

7x = 14

x = 2

4 - 2y = 2

-2y = -2

y = 1

Answer:

26 sqrt(5) + 2 sqrt(10)

Step-by-step explanation:

2 sqrt(5) *(13+sqrt(2))

Distribute

26 sqrt(5) + 2 sqrt(10)

Answer:

[tex]26\sqrt5 +2 \sqrt10[/tex]

Step-by-step explanation:

Answer:

a) x=3

b) x=4.5

Step-by-step explanation:

2(5x – 3) = 24

10x-6=24

10x=30

x=3

5(2x + 1) = 50

10x+5=50

10x=45

x=4.5

Answer:

the time taken for the 15 people to drink 155 pints is 20.67 min.

Step-by-step explanation:

Given;

10 people took 5 mins to drink 25 pints of water

[tex]The \ rate\ for \ 10 \ people = \frac{25 \ pints }{5 \ mins} = 5 \ \frac{pints}{\min} \\\\The \ rate \ for \ 1 \ person = \frac{5}{10} \ \frac{pints}{\min} = 0.5 \ \frac{pints}{\min} \\\\The \ rate \ for \ 15 \ people = 15( 0.5 \ \frac{pints}{\min} )= 7.5 \ \frac{pints}{\min} \\\\Time \ taken \ for \ the \ 15 \ people \ to \ drink \ 155 \ pints = \frac{155 \ pints}{7.5 \ pints/ \min} \\\\= 20.67 \min[/tex]

Therefore, the time taken for the 15 people to drink 155 pints is 20.67 min.

Answer:

The answer is $2.50

Answer:

the answer would be c because c= $2.50

Step-by-step explanation:

=============================================

Explanation:

Refer to the diagram below. The goal is to find x, which is the horizontal distance from the base of the tree to the swing set.

Focus on triangle BCD.

The angle B is roughly 30.26 degrees, and this is the angle of depression. This is the amount of degrees Emir must look down (when starting at the horizontal) to spot the swing set.

We know that he's 14 ft off the ground, which explains why AB = CD = 14.

The goal is to find BC = AD = x.

---------------------------

Again, keep your focus on triangle BCD.

We'll use the tangent ratio to say

tan(angle) = opposite/adjacent

tan(B) = CD/BC

tan(30.26) = 14/x

x*tan(30.26) = 14

x = 14/tan(30.26)

x = 23.9965714046732

That value is approximate. Make sure your calculator is in degree mode.

That value rounds to 24 feet when rounding to the nearest whole foot.

Using the slope concept, it is found that the base of the treehouse is 24 feet from swingset.

In this problem:

Hence:

[tex]\tan{30.26^{\circ}} = \frac{14}{x}[/tex]

[tex]0.5834 = \frac{14}{x}[/tex]

[tex]x = \frac{14}{0.5834}[/tex]

[tex]x = 24[/tex]

The base of the treehouse is 24 feet from swingset.

You can learn more about the slope concept at brainly.com/question/18090623

Answer:

ratio of Sophia's sweets to Isabel's sweets is

13:8

Answer:

you first have to find the number of sweets that sophia got.by subtracting the total number of sweets minus the number of sweets that isabel got which will be

42-16=26

therefore the ratio will be

16:26

8:13

I hope this helps

Answer:

3.25 minutes

Step-by-step explanation:

3.25 minutes per green light x 24 = 78

the yellow light is a given, hence 6 cars pass through

78 + 6 = 84 cars

Answer:

1/144

Step-by-step explanation: I presume..

And recall something from Algebra...

I hope it helps...

Square it

And reverse it because of the negative

It is a fraction

Answer:

[tex] = { \sf{ \frac{1}{ 144 } }}[/tex]

Step-by-step explanation:

[tex] = { \tt{ \frac{1}{ {12}^{2} } }} = \frac{1}{144} [/tex]

Answer:

slope = - [tex]\frac{8}{5}[/tex]

Step-by-step explanation:

Calculate the slope m using the slope formula

m = [tex]\frac{y_{2}-y_{1} }{x_{2}-x_{1} }[/tex]

with (x₁, y₁ ) = (23, - 30) and (x₂, y₂ ) = (- 7, 18)

m = [tex]\frac{18-(-30)}{-7-23}[/tex] = [tex]\frac{18+30}{-30}[/tex] = [tex]\frac{48}{-30}[/tex] = - [tex]\frac{8}{5}[/tex]

Answer:

B

Step-by-step explanation:

Sin x°= opposite ÷ hypotenuse

Cos x°= adjacent ÷ hypotenuse

Tan x°= opposite ÷ adjacent

Ctg x°= adjacent ÷ opposite

The correct will bet cot x = adjacent ÷ opposite

Trigonometry is a branch of mathematics that studies relationships between side lengths and angles of triangles.

Using trigonometric properties we have

Learn more about trigonometry here:

https://brainly.com/question/17103461

#SPJ5

Answer:

The possible approximate frequencies of the guitar string are 516.82 Hz and 508.82 Hz

Step-by-step explanation:

The given period of the tuning fork, T₁ = 1.95 × 10⁻³ s

The number of beats in 6.0 s = 24 beats

Therefore, the beat frequency, [tex]f_{beat}[/tex] = 4 beats per second = 4 Hz

Let f₁ represent the frequency of the tuning fork, and let f₂ represent the frequency of the guitar string, we have;

f₁ = 1/T₁ = 1/(1.95 × 10⁻³) ≈ 512.82 Hz

We have;

[tex]f_{beat} = \left | f_2 - f_1 \right |[/tex]

[tex]\pm f_{beat} = f_2 - f_1[/tex]

Therefore, we get;

[tex]4 \, Hz= \left | f_2 - 512.82 \, Hz \right |[/tex]

f₂ - 512.82 = ± 4

∴ f₂ = 512.82 ± 4

The possible frequencies of the guitar string,  f₂ ≈ 516.82 Hz or f₂ ≈ 508.82 Hz

Answer:

(1/9)^2 x 1/3

Step-by-step explanation:

1/243

=> 1 / 3 x 3 x 3 x 3 x 3

=> 1 / 9 x 9 x 3

=> (1/9)^2 x 1/3

Answer:

x + y + z.

Step-by-step explanation:

x² + y² + 2xy - z²

= (x + y)^2 - z^2

This is the difference between 2 squares so the factors are:

(x + y + z) and (a + y - z).

Answer: The factors are (x+y+z) and (x+y-z)

In other words, it factors to (x+y+z)*(x+y-z)

=====================================================

Work Shown:

[tex]x^2 + y^2 + 2xy - z^2\\\\(x^2 + 2xy + y^2) - z^2\\\\(x+y)^2 - z^2\\\\(x+y+z)(x+y-z)\\\\[/tex]

Notes:

Answer: width:60.2 cm

Length: 64.2 cm

Step-by-step explanation:

Given

The area of the rectangle is [tex]3990\ cm^2[/tex]

Width of the rectangle is [tex]x\ cm[/tex]

Length of the rectangle is [tex]x+4\ cm[/tex]

Area of the rectangle is the product of length and width

[tex]\therefore 3990=(x+4)x\\\Rightarrow 3990=x^2+4x\\\Rightarrow x^2+4x-3990=0\\\Rightarrow x=60.198\ or\ -65.198\ cm\\\text{Neglecting negative term}\\\Rightarrow x=60.198\approx 60.2\ cm[/tex]

Width of the rectangle is [tex]60.2\ cm[/tex]

Length of the rectangle is [tex]60.2+4=64.2\ cm[/tex]

Answer:

43.49

Step-by-step explanation:

let his normal hourly rate be x

16x+7x/2=848

39x/2=848

x=848 ÷ 39/2

=43.48717

Answer:

An electric company calculates a person's monthly bill from the number of kilowatt-hours (kWh), x, used, x 200 The function b(ar) = { 0.102, 0.15(x - 200) +20, 200 determines the bill How much is the bill for a person who uses 800 kWh in a month?

Answer:

240 cubic cm

Step-by-step explanation:

Volume of a cone = 1/3(nr^2h)

volume of a cylinder = nr^2h

n = 22/7

r = radius

The volume of a cone is 1/3 that of a cylinder

to determine the volume of the cylinder with the same parameters as a cylinder, multiply the volume of the cone by 3

80 x 3 = 240 cubic cm

Answer:

C

Step-by-step explanation:

Given

[tex]\frac{x^2-16}{(x-16)(x+4)}[/tex]

The numerator is a difference of squares

x² - 16 = (x - 4)(x + 4)

= [tex]\frac{(x-4)(x+4)}{(x-16)(x+4) }[/tex] ← cancel the common factor (x + 4) on numerator/ denominator

= [tex]\frac{x-4}{x-16}[/tex] → C

Answer:

Step-by-step explanation:

On first day , the video was viewed = 320 times .

We are given that Each day since then, the number of views was 25% more than the day before. This means the likes are increasing 1.25 per day .

So, this situation forms G.P.

Where common ratio r = 1.25

First term = f(1) = 320

Formula of nth term in G.P. =

So, nth term of the given situation :

Where f(n) denotes the number of views on nth day .

So, the number of views Vera's video got on the nth day =

Step-by-step explanation:

Answer:

x ≈ 94.4

Step-by-step explanation:

Using the tangent ratio in the right triangle

tan58° = [tex]\frac{LM}{KL}[/tex] = [tex]\frac{x}{59}[/tex] ( multiply both sides by 59 )

59 × tan58° = x , then

x ≈ 94.4 ( to the nearest tenth )

[tex] \sf3m + 12 = 15 \\ \sf3m = 15 - 12 \\ \sf3m = 3 \\ \sf \: m = \frac{3}{3} \\ \sf \: m \: = \underline{ \bf \: 1}[/tex]

-> Just move all the numbers from the left side to the right side until only the variable is left. Then you can solve the equation & find the required value.

3 m+ 12 = 15

⇔3 m=  3

⇔m=  1

Answer:

70

Step-by-step explanation:

we have the angle of vertex in the isosceles triangle = 180-2*bottom coner= 180-65/2=50

3 angles in the equilateral triangle are equal to 60

we have 50 + 60 +h =the angle of PQR =180

h=70

Answer: h = 70°

In the triangle with Angle R = 65

It is a isoceles triangle as two sides are equal

So base angles will be equall too

Then the third angle will which is the q one will be

65+65+q = 180

q = 180 - 130

q = 50

In the other triangle with all sides equal will be equilateral triangle which means all angles equal = 60

So

Now ATQ

60 + 50 + h = 180

h = 180 - 110 (Angles on a straight line adds upto 180)

h = 70

Must click thanks and mark brainliest

Answer:

cot a = 3 3/7

or, cot a = 24/7

or, tan a = 7/24

So,

cos a = 24/25

tan a = 7/24

Answered by GAUTHMATH

Answer:

d 28.8cm2

Step-by-step explanation:

1/2BH

1/2() 12.8() 4.5

28.8

Answer:

for every minute it will cost 3 dollars

Step-by-step explanation:

c(x)=3x+2.00

The cost to get in the taxi is 2 dollars

The slope is 3

3x means that for every minute it will cost 3 dollars

Answer:

Do you need it in percentage, a graph or just normal annual calculation?