Expert: Lynn Houston - 12/30/2008

Question
If Tom can mow the lawn in 6 hours and Kelly can mow the lawn in 5 hours.  How long will it take them to mow the lawn if they work together?

Answer
The secret to these type of questions is to put them into equivalent time frames.  Let's use 1 hr.  In one hr, Tom can do 1/6 of mowing a lawn and Kelly can do 1/5 of the job, so together, in one hour they can paint 1/5+1/6 or 11/30 of the house.  11/30x=1  x = 30/11 or 2 8/11 = 2 hrs and 44 mins to mow the lawn working together.