gwd 17-20

Q20:

For any integers x and y, min(x, y) and max(x, y) denote the minimum and the maximum of x and y, respectively.  For example, min(5, 2) = 2 and max(5, 2) = 5.  For the integer w, what is the value of min(10, w) ?

(1)     w = max(20, z) for some integer z.

(2)     w = max(10, w)

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: D

我选B

For any integers x and y, min(x, y) and max(x, y) denote the minimum and the maximum of x and y, respectively.  For example, min(5, 2) = 2 and max(5, 2) = 5.  For the integer w, what is the value of min(10, w) ?

(1)     w = max(20, z) for some integer z.

(2)     w = max(10, w)

条件（1），如果z>20, w=z, w>20  min(10,w)=10

                       如果z<20, w=20, min(10, w)=10

条件（2），w = max(10, w)  w>10  min(10,w)=10

答案是D.

(1)     w = max(20, z) for some integer z.

--> max(20,z) is w, so w=20,

(the first condition is alittile tricky)

(2)     w = max(10, w)

---> w > 10

D

no, i didn't agree D.

For first one. w = max(20, z) for some integer z, W=Z, if Z>20