math
posted by Anonymous on .
if wayne completed a task in one hour and sarah completed a task in two hours, how long will they take if they work together?

Every hour Wayne completes 1 task, and Sarah completes (1/2) task (simply take the reciprocal). Together, in 1 hour they will complete 3/2 tasks. Therefore, to complete 1 task, it takes them 2/3 hours.