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Machine A produces pencils at a constant rate of 9000

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VP
Joined: 22 Nov 2007
Posts: 1080
Machine A produces pencils at a constant rate of 9000 [#permalink]

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27 Dec 2007, 08:53
This topic is locked. If you want to discuss this question please re-post it in the respective forum.

Machine A produces pencils at a constant rate of 9000 pencils per hour, and machine B produces pencils at a constant rate of 7000 pencils per hour. If the 2 machines together must produce 100.000 pencils and if each machine can operate for at most 8 hours, what is the least amount of time, in hours, that machine B must operate?

A. 4
B. 4+2/3
C. 5+1/3
D. 6
E. 6+1/4
Director
Joined: 12 Jul 2007
Posts: 858

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27 Dec 2007, 09:00
Two machines. One makes 9,000 pencils and hour and the other makes 7,000. Each can work a maximum of 8 hours. What's the minimum amount that B (the 7,000 pencil machine) can operate?

The least amount of time would be when machine A works the full 8 hours.

9000*8 = 72,000

100,000-72,000=28,000 pencils left for B to make

28,000/7,000 = 4 hours of work for B.

27 Dec 2007, 09:00
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