Question

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

Answer 1

Answer:

56 minutes

Step-by-step explanation:

Since, when $x_1$ people complete $w_1$ work in $n_1$ days and the same kind of $w_2$ work is done by $x_2$ people in $n_2$ days,

Then,

$\frac{x_1\times n_1}{w_1}=\frac{x_2\times n_2}{w_2}$

Here,

$x_1 = 8, n_1 = 40, w_1 = 4, x_2 = 10, w_2 = 7$

$\implies \frac{8\times 40}{4}=\frac{10\times n_2}{7}$

$\frac{320}{4}=\frac{10n_2}{7}$

By cross multiplication,

$320\times 7 = 4\times 10n_2$

$\implies n_2 = \frac{320\times 7}{40}=8\times 7 = 56$

Hence, it will take 56 minutes to paint 7 walls by 10 people.

Answer 2

Its not 70 its 56, because you have to see how many minutes it takes for 1 to do 4 walls which would be 40*8.
Then you have to see if how many minutes its take a person to do one wall which is 8*40/4 from getting the amount of the 1 person doing 4 walls and get 80.
Then you need to see how many walls a person can paint 7 walls out of 10 people.So, we know how many minutes for each wall which is 80 and then multiply it by 7 to get 560 and divide it by 10 to get a product of 56.