Q16:

If k is a positive integer, what is the remainder when 2^k is divided by 10 ?

(1)   k is divisible by 10.

(2)   k is divisible by 4.

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.

Answer:   

2^4=16,

16的任意次方，结果的个位都是6，被10除，余数都是6