SOLUTION: Jim can build a desk in 4 hours. Matt can build the same desk in 6 hours. If Jim and Matt work together, how many hours will it take to build the desk.

Algebra ->  Rate-of-work-word-problems -> SOLUTION: Jim can build a desk in 4 hours. Matt can build the same desk in 6 hours. If Jim and Matt work together, how many hours will it take to build the desk.      Log On


   



Question 477702: Jim can build a desk in 4 hours. Matt can build the same desk in 6 hours. If Jim and Matt work together, how many hours will it take to build the desk.
Found 2 solutions by Alan3354, Maths68:
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
Consider what part of a desk each can build in an hour.

Answer by Maths68(1474) About Me  (Show Source):
You can put this solution on YOUR website!
Jim's work in an hour
4 hours…………………….. 1 desk
Divide by 4 both sides
4/4 hour…………………………… 1/4 desk
1 hour…………………….. 1/4 desk
So Jim can build one fourth of the desk in 1 hour
Matt's work in an hour
6 hours............ 1 desk
Divide by 6 both sides
6/6 hour............ 1/6 desk
1 hour.............. 1/6 desk
So Matt can build one sixth of the desk in 1 hour
In an hour Jim will complete 1/4 of desk and Matt will complete 1/6 desk
1 hour = (Jim's work + Matt's work)
1 hour = 1/4+1/6 desk
1 hour = (3+2)/12
1 hour = 5/12 desk
Multiply both sides by 12/5
12/5 * 1 hour = 5/12 * 12/5 desk
12/5 hours = 1 desk
2 2/5 hours
or
2.40 hours.