SOLUTION: Steve can complete his homework in 4 hours. If he gets help from Donald, he can complete it in 3 hours. How long does it take Donald to complete the homework working alone?

Question 942059: Steve can complete his homework in 4 hours. If he gets help from Donald, he can complete it in 3 hours. How long does it take Donald to complete the homework working alone?
Answer by lwsshak3(11628) (Show Source): You can put this solution on YOUR website!
Steve can complete his homework in 4 hours. If he gets help from Donald, he can complete it in 3 hours. How long does it take Donald to complete the homework working alone?
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Steve can complete his homework in 4 hours.
1/4= his work rate
Donald can complete his homework in x hours.
1/x=his work rate
working together they can complete the homework in 3 hours.
1/3=work rate working together
sum of indv. work rates=work rate working together
..
1/4+1/x=1/3
1/x=1/3-1/4
1/x=4/12-3/12=1/12
x=12
How long does it take Donald to complete the homework working alone? 12 hrs
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