SOLUTION: With a power mower, Phil can cut a large lawn in 3 hours. His younger brother can cut the same lawn in 6 hours. If they both work together using two power mowers, how long would

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Question 50228: With a power mower, Phil can cut a large lawn in 3 hours. His younger brother can cut the same lawn in 6 hours. If they both work together using two power mowers, how long would it take them to cut the lawn?
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
Phil can cut a large lawn in 3 hours. His younger brother can cut the same lawn in 6 hours. If they both work together using two power mowers, how long would it take them to cut the lawn?
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Phil DATA:
time = 3 hr/job ; rate= 1/3 job/hr
Brother DATA:
time = 6 hr/job ; rate = 1/6 job/hr
Together DATA:
time = x hr/job ; rate = 1/x job/ hr.
EQUATION:
Phil rate + Brother rate = rate together
1/3 + 1/6 = 1/x
Multiply thru by 6x to get:
2x + 3x = 6
5x = 6
x= 6/5 hours to do the job together
6/5 hrs = 72 minutes or 1 hr 12 minutes.
Cheers,
Stan H.