Sally can paint a room in 5 hours while it takes Steve 9 hours to paint the same room. How long would it take them to paint the room if they worked​ together?

Answer 1

Work formula: 1/time for job 1 + 1/time for job 2 = 1/time working together

Let x = time working together

Plugging in values:

1/5 + 1/9 = 1/x Common denominator

9/45+5/45 = 14/45 = 1/x Take the reciprocal

x=45/14 as a decimal

x = 3.2 hours working together