请教几个数学问题

ypl214 · 发表于 2010-7-21 13:04:15

1For every positive integer n,the function h(n) is defined to be the product of all the even integers from 2 to n.If p is the smallest prime of h(100)+1,then p is
A between 2 and 10
B between 10 and 20
C between 20 and 30
D between 30 and 40
E greater than 40
2 The rate of a certain reaction id directly proportional to the square of the chemical A present and inversely propotional to the concentration of chemical B present.If the concentration 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?

答案是40% increase

ypl214 · 发表于 2010-7-21 17:23:40

顶一下主要是第二个咋做

mmyiru · 发表于 2010-7-21 23:55:41

1. E

2. Let reaction rate be r, then r = A^2/B

如果分母增加为2B, 为了保证r不变，分子必须增加为 2*A^2 =(根号下2A)^2, 所以A必须从A增加为（根号下2)*A = 1.414 A. 也就是大概增加了40%

ypl214 · 发表于 2010-7-22 08:57:45

多谢了

请教几个数学问题

所属分类: GMAT考试

正在浏览此版块的会员 ()