SOLUTION: BILL CAN BUILD A BOOKCASE IN 6 HOURS, BUT IT TAKES HIS FRIEND, DAVID, ONLY 4 HOURS TO BUILD THE SAME BOOKCASE. HOW LONG WILL IT TAKE THEM TO BUILD THE BOOKCASE IF THEY WORK TOGETHE

Question 170417: BILL CAN BUILD A BOOKCASE IN 6 HOURS, BUT IT TAKES HIS FRIEND, DAVID, ONLY 4 HOURS TO BUILD THE SAME BOOKCASE. HOW LONG WILL IT TAKE THEM TO BUILD THE BOOKCASE IF THEY WORK TOGETHER?
GIVE THE ANSWER IN HOURS AND MINUTES
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
BILL CAN BUILD A BOOKCASE IN 6 HOURS, BUT IT TAKES HIS FRIEND, DAVID, ONLY 4 HOURS TO BUILD THE SAME BOOKCASE. HOW LONG WILL IT TAKE THEM TO BUILD THE BOOKCASE IF THEY WORK TOGETHER?
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Bill DATA:
Time = 6hrs/job ; rate = 1/6 job/hr
--------------------------------------
Davis DATA::
Time = 4 hrs/job ; rate = 1/4 job/hr
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Together DATA:
Time = x hrs/job ; rate = 1/x job/hr
----------------------------------------
EQUATION:
rate + rate = together rate
1/6 + 1/4 = 1/x
(10/24) = 1/x
x = 24/10 = 2.4 hrs
--------
0.4 hrs = 0.4*60 minutes = 24 minutes
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Answer: 2 hrs and 24 minutes (time they need to do the job together)
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Cheers,
Stan H.
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