Problem Solving
试题详情
题目：
If x , y , and k are positive numbers such that (
)(10) + (
)(20) = k and if 
, which of the following could be the value of k ?
)(10) + ()(20) = k and if , which of the following could be the value of k ?选项:
A、10
B、12
C、15
D、18
E、30
答案:
D
