求助]

guyan

求助大虾们几道数学题， 是princeton 模考上的
1.what is the maxmimum capacity , in cups, of a pail that contains only sand and is filled to three-fourths of its capacity?
1)if one cup of sand were added to the pail, it would then be filled to sevevn -eighths of its capacity.
2)if two cups were removed from the pail, it would then be filled to one-hail of its capacity.
答案是D 我不知道怎麽算。
2.five people meet and exchange shakehands, if exactly 3 of the people each shake hands with 3 people, and if 1 person shakes hands with only 1 other person, then what is the least number of handshakes that would have been exchanged.
答案是6， 不知是不是P33算出的。
3 in a survey of parents, exactly 3/4 of the mothers and 9/10 of fathers held full-time jobs, if 40percent of the parents surveyed were women, what percent of the parents did not hold full-time jobs?
干脆不明百！
谢谢谢谢万分感谢！

卧室春竹

第二个题

应该是3*2*1 呵呵

当一个人 和确定的一个人握手后 剩下的二个人中的一个 他有2个人选择握手

然后最后一个人就一个选择

然后答案就是 3*2

呵呵 好像说得不清楚啊？ 对吗？？

renali

第1道题:
1) a pail has x cups: x*3/4+1=x*7/8  => x=8 cups
2) same as 1)  => ans D

第2题: who can tell us how to get the answer?

mimi

第三道题是1/4*40%+1/10*60%=16%