Question

If Timmy can do 1/3 of the yardwork in 1 hr and Tommy can do 1/4 of the yardwork in 1 hr, how much of the yardwork can they do in 1 hr working together?

1/12
7/12
1/7
none of the answer choices

Answer 1

Add their hourly rates: 1/3 + 1/4 = 4/12 + 3/12 = 7/12.
So together they can do 7/12 of the yardwork in 1 hour.