Henry can paint a kitchen in 20 hours and his assistance can do it in 30 hours. How long will it take them together?

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Answer 1 · 2016-04-17T20:56:15

12 hours

Henry paints #1/20# of the kitchen per hour

His assistent paints #1/30# of the kitchen per hour

Overal they paint per hour:

#1/20+1/30=3/60+2/60=5/60=1/12#

They will take #x# hours to complete the kitchen:

#1/12 x=1#

#x=12# hours