Posted by **M.A.** on Tuesday, September 28, 2010 at 8:16am.

Andy and William work together to build a toy house. It will take William 5 hours and Andy 4 hours, or William 10 hours and Andy 2 hours to finish their work. If William works alone, how many hours will it take to finish his work?

5

10

15

20

Explain how you arrived at the answer.

- math word problem -
**Dr Russ**, Tuesday, September 28, 2010 at 10:43am
There are two ways to do this, as a logic problem or as an algebra problem

If it will take William 5 hours and Andy 4 hours, or William 10 hours and Andy 2 hours to finish their work, then each decrease in time by Andy of 2 hours results in 5 more hours of work by William. So if Andy's work goes to zero then there will be 5 more hours of work required by William, so

10h + 5 h = 15 h.

By algebra if we say that the rate of work by William is x and that by Andy is y then

5x+4y=T Total task .....1

10x+2y=T

or

20x+4y=2T ..............2

subtract 1 from 2

15x=T, so it takes William 15 h

- math word problem -
**M.A.**, Tuesday, September 28, 2010 at 10:55am
Thank you Dr. Russ. I am so thrilled with your answer. It is the first time I have had an answer that I can truly understand and comprehend, being a math-challenged individual. Thank you sooo much for your careful and complete explanation!

## Answer This Question

## Related Questions

- Math - Andy and William work together to build a toy house. It will take William...
- Answer Check Please - Andy and William work together to build a toy house. It ...
- math - 10. A house painter can finish a house in 6 hours. His partner can finish...
- math - William earns $13 an hour working at a movie theater. Last week he worked...
- Math - William rode his bike 20 miles in 2 hours. Lorie rode her bike 30 miles ...
- math - if tony took 24 hours to finish his homework and sally took 30 hours. if ...
- 7th grade math - Q:William practiced guitar 1 1/3 hours on monday and 5/6 hour ...
- Math - Dorothy and Rosanne are baking cookies for a party. Working alone, ...
- URGENT MATH!! - Q1: Robert can paint a room in 12 hours. Dennis and Vince can ...
- Math 6th - Andy ran a 5-kilometer race in 40 minutes. If Andy maintains that ...

More Related Questions