Bunuel wrote:
Jim can assemble b crates an hour and Robert can assemble 2b crates in an hour. Working together at this rate, how many crates can they assemble in four hours?
A) 3b
B) 6b
C) 8b
D) 12b
E) 18b
Let's apply some logic to solve this question
Given: Jim can assemble b crates in 1 hourSo: Jim can assemble
2b crates in
2 hours
[if we double the work time, we double the output]So: Jim can assemble
4b crates in
4 hours
[if we double the work time (again), we double the output]Given: Robert can assemble 2b crates in 1 hourSo: Robert can assemble
4b crates in
2 hours
[if we double the work time, we double the output]So: Robert can assemble
8b crates in
4 hours
[if we double the work time (again), we double the output]So, when we COMBINE their efforts, we add their 4-hour OUTPUTS
That is, TOTAL output = color=red]4b[/color] + color=red]8b[/color] = 12b
Answer: D
Cheers,
Brent
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Brent Hanneson – Creator of gmatprepnow.com
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