Problema Solution

Hannah can paint a room in 12 hours. Destiny can paint the same room in 20 hours. How long does it take for both Hannah and Destiny to paint the room it they are working together.

Answer provided by our tutors

Hannah can paint a room in 12 hours thus her rate is 1/12 room per hour


Destiny can paint the same room in 20 hours thus her rate is 1/20 room per hour


let


x = the number of hours both Hannah and Destiny need to paint the room together


1/x room per hour = the together rate of Hannah and Destiny


1/12 + 1/20 = 1/x


by solving we find:


x = 7.5 hr


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it takes 7.5 hours for both Hannah and Destiny to paint the room together.