math 151 question

Question

Hannah can paint a room in 12 hours. Destiny can paint the same room in 15 hours. How long does it take for both Hannah and Destiny to paint the room it they are working together? Enter the exact time as an improper fraction if needed.

Answer 1

1/12 + 1/15 = 1/t

multiply by 60

5t +4t = 60t

9t = 60

t = 60/9 = 20/3 hours working together

= 6 2/3 hours

= 6 hours 40 minutes