Question 570820: Alice can vacuum in 40 minutes. It takes Bob 45 minutes to do the same job. Find the time it takes Alice and Bob to do the job together Answer by nerdybill(7384) (Show Source):
You can put this solution on YOUR website! Alice can vacuum in 40 minutes. It takes Bob 45 minutes to do the same job. Find the time it takes Alice and Bob to do the job together
Let x = time (minutes) it takes for both
then
x(1/40 + 1/45) = 1
multiplying (40)(45):
x(45 + 40) = (40)(45)
x(45 + 40) = 1800
x(85) = 1800
x = 1800/85
x = 21.18 minutes
