Question

eric kweeder can paint a wall in 20 mins. His brother Jessup can paint the same wall in 30 mins. How long will it take them working together?

Answer 1

We=1/20
Wj=1/30
Wt = 1/20+1/30 = 30/600 + 20/600 = 50/600 = 1/12
T= 1/rate = 1/(1/12) = 12 minutes.