标题: 问一道数学GWD31的第7套第3题 [打印本页] 作者: carolyn1106 时间: 2009-12-22 14:05 标题: 问一道数学GWD31的第7套第3题 Material A costs $3 per kilogram, and material B costs $5 per kilogram. If 10 kilograms of material K consists of x kilograms of material A and y kilograms of material B, is x > y? (1) y > 4
(2) The cost of the 10 kilograms of material K is less than $40.
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.
我选的是A, 答案是B,我怎么看怎么不对呀~请教一下大家了~作者: a10285 时间: 2009-12-22 15:18
x = y则K = $4/kilo x>y K < $4/kilo x<y K > $4/kilo