[求助]GWD3-16 和 28

lingdang1988

Each of the 30 boxes in a certain shipment with either 10 pounds or 20 pounds, and the average (arithmetic mean) weight of the boxes in the shipment is 18 pounds. If the average weight of the boxes in the shipment is to be reduced to 14 pounds by removing some of the 20-pound boxes, how many 20-pound boxes must be removed?

A. 4

B. 6

C. 10

D. 20

E. 24

Q16:

If m, p, and t are positive integers and m < p < t, is the product mpt an even integer?

(1) t – p = p - m

(2) t – m = 16

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

mindfrees

16，10X+20Y=18*30,X+Y=30.....X=6,Y=14

10*6+20Z=14(6+Z).............Z=4 Y-Z=10

28,E

moderation

16中的t=p(m+1) mpt=m(m+!)p^2 连续２个数相乘　有一个必为偶数，所以mpt 为偶数，为何不选Ａ？请各位ＸＤＪＭ帮帮偶......