pp-t1-ps-36

[yiyiyi]

In a certain deck of cards, each card has a positive integer written on it. In a multiplication game, a child draws a card and multiplies the integer on the card by the next larger integer. If each possible product is between 15 and 200, then the least and greatest integers on the cards could be

(A) 3 and 15
(B) 3 and 20
(C) 4 and 13
(D) 4 and 14
(E) 5 and 14

ans: C
Why not D?

[aqboy[origen]]

(D) 14x15=210>200 --->wrong

(c) 13x14=182<200---->right

[larry.tw]

我不太懂位啥C耶

C最大值不是應該12x13=156
D最大值不是應該13x14=182(比較符合<200阿??)

請解釋一下,Thanks!

[Philosophia]

because multiplies the integer on the card by the next larger integer

當小朋友手上的牌是13時，13 x 14 = 182 < 200
當小朋友手上的牌是14時，14 x 15 = 210 > 200

所以若要符合題目限制，小朋友手上最大的牌只能是13.

[larry.tw]

可是
當小朋友手上的牌是14時，如果乘以15不就表示還有15可以拿?而且14也就不是最大值啦~~

這根本就是圖利美國人的題目阿><"霧煞煞~~~

[Philosophia]

because a child draws a card and multiplies the integer on the card by the next larger integer, it will not happen he/she gets a card with number 14.