GMAT数学考试2-HEIGHT题型介绍

    举个例子吧，40=2*2*2*5，即2的三次方乘以5，3就是2-height 的值，再如12=2*2*3，即2的二次方乘以3，所以2就是2-height 的值。

总的来说，就是把一个GMAT数学整数分解成质数的乘积，其中2的幂就是2-height 的值。

10、For all x, x is positive integer, "2-height" is defined

to be the greatest nonnegative n of x, what is the

greatest number of 2-height when 2" is the factor of x?

A. 2

B. 12

C. 40

D. 76

E. 90

Answer: (by Anchoret)

A. 2=2^1

B. 12=2^2*3

C. 40=2^3*5

D. 76=19*2^2

E. 90=45*2^1

B is the answer.

1. X is a positive integer. 2-height of X is defined as the greatest negative integer n where 2^n is a factor of X. K and M are two positive integers. Whether 2-height of K is greater than 2-height of M?

a. K is greater than M

b. K is even times of M

(Key: B)

(by rosemsem)

题义解析：GMAT考试说对于含2的n次方的数, 2-height 指的是n的值。问k和m谁的2-height大?

(1) K>M

(2) K除以M是偶数.

(please notice K,k; M,m; e)

K = a* 2^k;

M = b* 2^m;

(1) k>m, means nothing.

(2) k/m= (a/b) * (2^k/2^m) = 2^e;

A, b must be odd number, or you can extract at least one more 2, which gonna change k or m. So in this case, (a/b) must be 1, otherwise it would be a fraction.

In a word, k-m=e. K>m.

B is sufficient.GMAT入门的同学要了解一下。