Question

A group of college students are volunteering for Help the Homeless during their spring break. They are putting the finishing touches on a house they built. Working alone, Irina can paint a certain room in 8 hours. Paulo can paint the same room in 7 hours. Write an equation that can be used to find how long it will take them working together to paint the room. How many hours will it take them to paint the room? If necessary, round your answer to the nearest hundredth

Answer 1

It probably be answer letter b

Answer 2

Time taken by both is 3 hours and 44 minutes.

Explanation:

Working alone, Irina can paint a certain room in = 8 hours

Working alone, Paulo can paint the same room in = 7 hours

Let the time required when they work together be = t

Let the completed job be = 1

Both will do a fraction of the job and the two fractions add up to 1.

Equation becomes:

`(t)/(8)+(t)/(7)=1`

Now solving this we get

`(7t+8t)/(56) =1`

`15t=56`

t= 3.73 hours

This becomes 3 hours and 0.73(60)=43.8 ≈ 44 minutes.

Therefore, time taken by both Irina and Paulo is 3 hours and 44 minutes.