[讨论] 几道数学题

Henrik

30 What is the value of the greater of two numbers if one of the number is twice the other number?

1) One number is 5

2) The sum of the two numbers is 15.

A

2)  为什么不对呢?

The rate of a certain chemical reaction is directly proportional to the square of the concentration of chemical A present and inversely proportional to the concentration of chemical B present. If the concentration of chemical B is increased by 100 percent, which of the following is closest to the percent change in the concentration of chemical A required to keep the reaction rate unchanged?

40% increase.

(一点思路也没有)

谢谢

ted810

第一题我也不知道为啥2条件就不行

第二题其实就是X＝A^2/B。B翻了一番，问A要增加多少X才基本无变化。1.4的平方是1.96，接近2。所以是增加40％。

EUR的小睡猫

我觉得第一题的答案应该为（1）不sufficient （2）sufficient

题意为：一个数为另一个数的两倍，问较大的数是多少

解答：（1）从一个为5并不能得知它是小的那个数还是大的数，所以不满足。

            （2）可以得知大的数为10，所以正确。

Henrik

谢谢,

第一题PREP上的答案是A.