问题
单项选择题
If tank X contains only gasoline, how many kiloliters of gasoline are in tank X ？（）
(1)If 
of the gasoline in tank X were pumped out the tank would be filled to 
of its capacity.
(2)If 0.75 kiloliter of gasoline were pumped into tank X, it would be filled to capacity.
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：C
解析：
很明显，(1)和(2)单独都不充分。设油罐X的容量为a千升，则根据(1)可得油罐X中的汽油为其容量的[*]，即为[*]千升；再根据(2)可知0.75千升的汽油占油罐容量的[*]，从而可得出油罐中的汽油是0.75的2倍，即为1.5千升，所以(1)+(2)充分。