Q27:

The sum of positive integers x and y is 77.  What is the value of xy?

(1)     x = y + 1

(2)     x and y have the same tens digit.

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.

B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.

C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.

D. EACH statement ALONE is sufficient.

E. Statements (1) and (2) TOGETHER are NOT sufficient.

为什么是D,明明是A拉

明明是D拉

７７＝３８＋３９，　还有其他吗？

[此贴子已经被作者于2006-8-4 9:31:27编辑过]

是D

x y 只能是 38 和 39 ，或者 39 和 38

但是先后顺序并不影响他们的乘积