It takes Nate four hours to paint a wall, and it takes Jill seven hours to paint the same wall. About how many hours will it will take if Nate and Jill work together to paint the wall?

11 hours

5.5 hours

2.5 hours

1.5 hours

Question

It takes Nate four hours to paint a wall, and it takes Jill seven hours to paint the same wall. About how many hours will it will take if Nate and Jill work together to paint the wall?


		
11 hours

		
5.5 hours

		
2.5 hours

		
1.5 hours

astrophysics · Answer

@ParthKohli

parthkohli · Answer

in an hour, Nate does 1/4th of the work and Jill does 1/7th of the work. If both work together, they'll do (1/4+1/7)th of the work in an hour.

1/4 + 1/7 = 11/28th of the work. 

So they'll require 28/11 hours.

astrophysics · Answer

ty

parthkohli · Answer

dogs4dogs

diana.xl · Answer

so would my answer be 2.5 hours?

welshfella · Answer

here you can  use the  rate/hour of painting the wall
Nate paints 1/4 of the wall in one hour, Jill paints 1/7 :-

1/4  + 1/7 = 1/x

where x is the time if they work together

anonymous · Answer

crap you guys both beat me

anonymous · Answer

i was busy helping someone else @Astrophysics  @ParthKohli

welshfella · Answer

the answer is 28/11 = 2 6/11  hours  or 2.55 hours  to nearest hundredth

directrix · Answer

The equation of @welshfella is correct.

directrix · Answer

>28/11 = 2 6/11 hours or 2.55 hours

Or, 2 hours and 33 minutes, approximately

@Diana.xL