问题
单项选择题
At a certain state university last term, there were p students each of whom paid either the full tuition of x dollars or half the full tuition. What percent of the tuition paid by the p students last term was tuition from students who paid the full tuition ？（）
(1)Of the P students, 20 percent paid the full tuition.
(2)The p students paid a total of $91.2 million for tuition last term.
A．条件(1)充分，但条件(2)不充分．
B．条件(2)充分，但条件(1)不充分．
C．条件(1)和(2)单独都不充分，但条件(1)和条件(2)联合起来充分．
D．条件(1)充分，条件(2)也充分．
E．条件(1)和条件(2)单独都不充分，条件(1)和条件(2)联合起来也不充分．
答案
参考答案：A
解析：
(1)充分，因为由(1)中付全额学费的学生有20%，可以推知付全额学费的学生所付的学费所占的百分比为：
[*]
(2)不充分，因为从学费的总量中无法得出付全额学费的学生所付的学费在总学费中占的比例方面的信息。