Question 641053: If Sally can paint a house in 4 hours, and John can paint the same house in 6 hours, how long will it take for both of them to paint together? Hi I know the answer , but I dont know how to do it. Please elaborate. Thanks, Nelida.
Answer by lwsshak3(11628)   (Show Source):
You can put this solution on YOUR website! If Sally can paint a house in 4 hours, and John can paint the same house in 6 hours, how long will it take for both of them to paint together? Hi I know the answer , but I dont know how to do it. Please elaborate.
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Sally can alone paint a house in 4 hrs,
her work rate=1/4 house per hr
..
John can alone paint a house in 6 hrs,
his work rate=1/6 house per hr
..
Working together Sally and John can paint the house in x hours
Their work rate working together=1/x
..
sum of individual work rates=work rate working together
1/4+1/6=1/x
3/12+2/12=1/x
5/12=1/x
x=12/5=2.4
Working together Sally and John can paint the house in 2.4 hours
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