Problema Solution
Joe can mow a fairway in 4 hours. Bob can do it in 3 hours. Joe, Bob, and Tom working together can do it in an hour and 20 minutes. How long would it take Tom to do the job working alone?
Answer provided by our tutors
Let 'x' represent the hours that Tom need to finish the job alone, x>0.
1/x is the Tom's rate per hour
1/4 is Joe's rate per hour
1/3 is Bob's rate per hour
1/(20/60) = 1/(1/3) = 3 per hour is the together rate per hour (since 20 min = 20/60 hr = 1/3 hr)
1/x + 1/4 + 1/3 = 3
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click here to see the equation solved for x
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x = 12/29 hr
x = 12*60/29 min
x = 24.83 min
Tom needs 24.83 min approximately to finish the job alone.