[問題]OG(11th)PS-Q120

[凱薩琳]

One week a certain truck rental lot had a total of 20 trucks, all of which were on the Monday morning. If 50 pervent of the trucks that were rented out during the week were returned to the lot on or before Saturday morning of that week, and if there were at least 12 trucks on the lot that Saturday morning, what is the greatest number of different trucks that could have been rented out during the week?

(A)18
(B)16
(C)12
(D)8
(E)4

Ans:B

[StanleyHuang]

假設有K台被租出去，所以沒被租出去的就是20-K台
星期六早上有12台在停車場 所以 (20-K) + 0.5K = 12 可得 K = 16

至於OG官方的解答則是
有12台在停車場 => 有20-12=8台還在外面
又，50%的車都回來了，所以50%還在外面
因此，全部在外面的 = 8 / 50% = 16

[凱薩琳]

謝謝回答