All categories

4 years ago

It takes 40 minutes for 8 people to paint 4 walls. How many minutes does it take 10 people to paint 7 walls?

Mathematics

1 answer:

Aloiza [94]4 years ago

3 0

It is at least 80 by 10times 8

You might be interested in

If U= π(r+h), find r when U =16/1/2 and h = 2/3/4<br><br>π = 3/1/7

krek1111 [17]

Answer:

r = 2.5

Step-by-step explanation:

U= π(r+h)

Where,

U = 16 1/2

h = 2 3/4

π = 3 1/7

U= π(r+h)

16 1/2 = 3 1/7(r + 2 3/4)

33/2 = 22/7(r + 11/4)

33/2 = 22/7r + (22/7 * 11/4)

33/2 = 22/7r + 242/28

33/2 - 242/28 = 22/7r

(462-242) / 28 = 22/7r

220/28 = 22/7r

r = 220/28 ÷ 22/7

= 220/28 × 7/22

= (220 * 7) / (28 * 22)

= 1540/616

= 2.5

r = 2.5

4 0

3 years ago

Which expression represents the product of unknown number and 19?

Nina [5.8K]

It would be 19x because it is the same as 19 times x.

4 0

4 years ago

Read 2 more answers

WRITE Math Write two ways you could use to find 5 + 8.

valina [46]

Answer:

8+5 and 8--5

Step-by-step explanation:

minus and minus is plus and 5+8 =8+5

7 0

2 years ago

What is the average rate of change of the function f(x)=2(3)x from x = 2 to x = 4?

Umnica [9.8K]

The average rate of change of function is 72.

<u>SOLUTION: </u>

Given that, we have to find the average rate of change of the function f(x)=2(3)x from x = 2 to x = 4

Use the slope formula to find the average rate of change:

$\begin{array}{l}{m=\frac{y 2-y 1}{x 2-x 1}} \\\\ {m=\frac{f(4)-f(2)}{4-2}} \\\\ {m=\frac{f(4)-f(2)}{2}}\end{array}$

To simplify this, we need to find values of f ( 4 ) and f ( 2 ) :

$\begin{array}{l}{f(4)=2 x(3)^{4}=2(81)=162} \\\\ {f(2)=2(3)^{2}=2(9)=18} \\\\ {m=\frac{162-18}{2}} \\\\ {m=\frac{144}{2}} \\\\ {m=72}\end{array}$

6 0

3 years ago

A hot cup of coffee is 200F when poured and placed in a room that is 70F. 10 min later the temperature of the coffee has cooled

Marianna [84]

Answer:

The temperature of coffee becomes 163.08 Fahrenheit.

Step-by-step explanation:

The Newton's law of cooling can be mathematically written as

$-\frac{dT}{dt}=k(T-T_{room})\\\\\frac{-dT}{(T-T_{room})}=kdt$

Applying the limits in the above relation as

At t = 0 ; T= 200 F

At t =10 ; T = 180 F

$-\int_{200}^{180}\frac{dT}{T-70}=\int_{0}^{10}kdt\\\\-ln(T-70)_{200}^{180}=k\times 10\\\\\therefore k=\frac{ln(1.181)}{10}\\\\\therefore k=0.0167$

Applying the limits in the above relation as

At t = 10 ; T= 180 F

At t =20 ; T = T F

$-\int_{180}^{T}\frac{dT}{T-70}=\int_{10}^{20}0.0167dt\\\\-ln(T-70)_{180}^{T}=0.167\\\\\therefore T = 163.08F$

5 0

3 years ago

Read 2 more answers