Math word Problem

Question

Jamie and Pat volunteered to paint the hall in the E wing. If it would take Jamie 10 hours to paint the hall alone, and take Pat 5 hours to paint the hall alone, how long will it take them to paint the hall if they work together?

Answer 1

Assume that the wall is 100 ft² (This number is arbitrary.... you could use any reasonable positive number)

Then, if Jamie takes 10 hours, then Jamie paints 10 ft²/hour

if Pat takes 5 hours to paint the wall, then Pat paints 20 ft²/hour

Then, working together, they can paint 30 ft²/hour.

Since the wall is 100 ft², then 100 ft²/30 ft²/hour = 3.33 hours