Question 491846
James can mop a warehouse in 12 hours. One day his friend Molly helped him and it only took 4.8 hours. How long would it take Molly to do it alone?
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let 1/12= james' work rate
let 1/x= molly's work rate
1/4.8= work rate when James and Molly work together
..
Individual work rates=work rate when working together
1/12+1/x=1/4.8
4.8/12+4.8/x=1
.4+4.8/x=1
4.8/x=1-.4=.6
x=4.8/.6=8
Ans:
It would take Molly 8 hours to finish the job alone