Bunuel wrote:
Kramer can pack X boxes of cigarettes per minute. If there are Y boxes of cigarettes in one case, how many cases can Kramer pack in 2 hours?
A. 60X/Y.
B. 120X/Y.
C. 60Y/X.
D. 120Y/X.
E. (X + Y)/60.
Picking numbers. Seeing answer choices, for easier arithmetic, X should be small. Y should be large and a factor of 120.
X = 1 box/1 minute
Y = 60 boxes/1 case
X= \(\frac{1box}{1min}=\frac{60b}{60min}=\frac{60b}{1hr}\)
How many cases in 2 hours?
\(\frac{1case}{60b}*\frac{60b}{1hr}*2hrs=2 cases\)
With X = 1, and Y = 60, find the answer choice that yields 2.
Eliminate answers C and D immediately. Large numerators, tiny denominator. (X = 1) No chance of 2 as an answer.
Eliminate E, too, from the numerator: (X + Y) = 1 + 60 = 61, which is prime AND odd. No way it can yield 2.
A) 60X/Y: \(\frac{60*1}{60}=\) 1 case. Not a match.
B) 120X/Y: \(\frac{120*1}{60}=\) 2 cases. MATCH
Answer B
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Any fool can know. The point is to understand. — Albert Einstein