Home work, page-8

It takes the first man 2hrs and the second man 3hrs to paint a room.

In 2hrs the second man would have painted two thirds of the room so if they were painting together the second man will paint two thirds of what the first man paints.

Therefore: (2/3)y + y = 1, where y is the fraction of the room that the first man paints.

Solving for y gives y = 3/5.

So if the first man takes 2hrs to paint the room on his own it would take hime (3/5)x2 = 6/5 = 1.2hrs to paint 3/5ths of the room.

72 minutes.

BBM