Question

Mary can paint a house by herself in 12 hours. john can paint a house by himself in 16 hours. how long would it take them to paint the house if they worked together?

Answer 1

1/12+1/16=1/n
4/48+3/48=1/n
7/48=1/n
48=7n
n=48/7 hours to paint the house if they worked together
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