Question

It takes 36 minutes for 7 people to paint 4 walls.

How many minutes does it take 9 people to paint 7 walls?

Answer 1

49 minutes

Explanation:

first we need to find the rate at which a person paints the walls :

it takes 36 minutes to paint 4 walls by 7 people :

so for 7 people the rate at which they paint the walls is :
`(4)/(36)` walls/minute

if we simplify we get
`(1)/(9)`

now that was for 7 people , for 1 person the rate is :
`(1)/(9) (1)/(7)` which is
`(1)/(63) walls / minute`

now we have the rate for one person

so for 9 people they will paint
`(9)/(63) =(1)/(7)` walls/minute

so it takes them 7 minute to paint 1 wall

which means it takes them 7 x7 = 49 minutes to paint 7 walls

Answer 2

49 minutes

Explanation:

It would take 49 minutes for 9 people to paint 7 walls.

4 walls need 262 people/minutes (7)(36)

9 people could do that in 49 minutes (441/9)