Question 295713
Susan can paint a house in 4 hours. James can paint the same house in 6 hours. How long will it take to paint the house if Susan and James work together?
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Susan does 1/4 house per hour.
James does 1/6 house per hour.
Together, they do 1/4 + 1/6 per hour = 5/12
5/12 house/hour --> 12/5 hours/house
= 2.4 hours.
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Use the shortcut, product/sum
4*6/(4+6) = 24/10
= 2.4 hours