SOLUTION: jack usually mows the lawn in 3 hours. Sally mows the same yard in 4 hours. How much time would it take for them to mow the lawn together?

Question 588797: jack usually mows the lawn in 3 hours. Sally mows the same yard in 4 hours. How much time would it take for them to mow the lawn together?
Found 2 solutions by richwmiller, solver91311:
Answer by richwmiller(17219) (Show Source): You can put this solution on YOUR website!
x/3+x/4=1
4x+3x=12
7x=12
x=12/7=1.71429 hours

Answer by solver91311(24713) (Show Source): You can put this solution on YOUR website!

If A can do a job in x time periods, then A can do of the job in 1 time period. Likewise, if B can do the same job in y time periods, then B can do of the job in 1 time period.

So, working together, they can do

of the job in 1 time period.

Therefore, they can do the whole job in:

time periods.

John

My calculator said it, I believe it, that settles it

RELATED QUESTIONS
Jack usually mows his lawn in 5 hours. Marilyn can mow the same yard in 4 hours. How much (answered by mananth)
Jack usually mows his lawn in 7 hours. Marilyn can mow the same yard in 5 hours. How much (answered by dabanfield,Alan3354)
Jack usually mows his lawn in 5 hours. Mary can mow the same yard in 3 hours. how much... (answered by stanbon)
Jack usually mows his lawn in 3 hours. Marilyn can mow the same yard in 4 hours. How much (answered by solver91311)
Jack usually mows his lawn in 3 hours. Jill can mow the same yard in 4 hours. How much... (answered by richwmiller,dabanfield,J.A.Romero)
Jack usually mows his lawn in 5 hours. Mary can mow the same yard in 7 hours. how much... (answered by phd,edjones)
Please help me to solve : Jack usually mows the lawn in 3 hours. Marilyn can mow the same (answered by Edwin McCravy)
Jack usually mows his lawn in 4 hours. Marilyn can mow the same yard in 6 hours. How... (answered by LarsJongste,slim522)
Jack usually mows his lawn in 4 hours. Marilyn can mow the same yard in 5 hours. How... (answered by nerdybill)