请教两道prep里的数学题

aliciaxj

1. The cost of a square slab is proportional to its  thickness and also proportional to the square of its length. what is the cost of a square slab that is 3 meters long and 0.1meter thick?

(1)the cost of a square slab that is 2meters long and 0.2 meter thick is $160 more than the cost of a square slab that is 2 meters long and 0.1 meter thick.

(2) the cost of a square slab that is 3meters long and 0.1 meter thick is $200 more than the cost of a square slab that is 2 meters long and 0.1 meter thick.

正确答案是D

2.If the drama club and music club are combined, what the percentage of the combined membership will be male?

(1)Of the 16 members of the drama club, 15 are male.

(2)Of the 20 members of the music club, 10 are male.

 答案是E

snowwarm

第一题你先写出表达式：cost=k*thickness*length^2，k是要求的常数。然后(1)和（2）都可以让你解出k。

第二题，我怎么觉得是C呢。。。

lkmacathur

第二题只说了两个俱乐部的比例，所以没法求合并后的 所以是e

aliciaxj

哦，原来是这样啊，谢谢各位啦~