[問題]GWD 17-03

[媽媽教的好]

Q3:
If x and y are nonzero integers, is 18 a factor of xy^2 ?
(1) x is a multiple of 54.
(2) y is a multiple of 6.

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.

答案是給D 請問一下(2)這個選項要怎麼看呢??? 謝謝

[zazer.lin]

statement(2):
Because y is a multiple of 6, let y = 6n, n is an integer
xy[sup]2[/sup] = x(6n)[sup]2[/sup] = 36xn[sup]2[/sup] = 2*18*xn[sup]2[/sup]
We can get that 18 is a factor of xy[sup]2[/sup]

[媽媽教的好]

了解 謝謝您的回覆