GMATPREP 2 DS QUESTION

frankmfg

    

Of the 20 people
who each purchased 2 tickets to a concert, some used both tickets, some used
only 1 ticket, and some used neither ticket. 
What percent of the tickets that were purchased by the 20 people were
used by those people?

    

 

    

(1)  Of the 20 people, 10 used only 1 ticket.

    

 

    

(2)  Of the 20 people, 4 used neither ticket.

[此贴子已经被作者于2009/10/19 19:52:58编辑过]

frankmfg

help?

biglin1987

选c

（1）（2）结合可知10个人用了一个，4个人一个也没用，那么剩下的六个人每人用了2个，一共用了22个。

一共买了40张票，所以能算出是22/40。

（1）（2）单独都无法确定。