单选题 Pam and Ed are in a line to purchase tickets. How many people are in the line?
(1)There are 20 people behind Pare and 30 people in front of Ed.
(2)There are 5 people between Pam and Ed.
(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.

【正确答案】 E
【答案解析】[解析] (1)和(2)都明显不充分,但大多数的考生会认为(1)+(2)充分,他们认为此时队列中的人数应为30+1+15+1+20=57人。选择(C)选项的考生都假定认为Ed在Pam的前面,而实际上究竟Pam和Ed谁在前谁在后题目中并未给出,所以该队中有多少人就是不定的,当Ed在Pam的后面时,该队列中的人数为20+30-5=45人。