GWD31-8 三道数学求助！~！！

dolorez

9   为什么答案·是A啊？？？
The operation* represents either addition, subtraction, or multiplication of integers, what is the value of 1*0?
(1)    0*2=2  
(2)     2*0=2

?    statement (1) ALONE is sufficient, but statement (2) alone is not sufficient
?    Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient
?    BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
?    EACH statement ALONE is sufficient
?    Statements (1) and (2) TOGETHER are NOT sufficient


16
From May 1 to May 30 in the same year, the balance in a checking account increased. What was the balance in the checking account on May 30?
(1)    If, during this period of time, the increase in the balance in the checking account had been 12 percent, then the balance in the account on May 30 would have been $504
(2)    During this period of time, the increase in the balance in the checking account was 8 percent.

?    Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient
?    Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient
?    BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
?    EACH statement ALONE is sufficient
?    Statements (1) and (2) TOGETHER are NOT sufficient


20
Of the 32 students in a certain class, 15 are in a music club and 20 are in a dance club. If 10 of the students are not in either club, how many of the students are in only one of the two clubs?
A. 5   B. 9   C.10   D. 17   E. 25

huiguo85

第九题：我觉得是D,0*2=2，那么*必须是+，所有（1）成立；2*0=2，*可以是+，也可以是—，虽然*的符号不能确立，但是，不管是+还是—，1*0的值永远是1.


16题没看明白


20题：你把这道题以集合图形的方式画出来你就茅塞顿开了

D小妖

16 题：（1）（1+12%）X=504，可以算出月初X的值，但是没有增长比例，得不到结论

（2）给出增长比例，X（1+8%）=月末值

所以，我觉的选C

dolorez

我画的图啊。。。。画了后得到music club 2人，dance club 7人，，均参加的13人啊。。。均不参加的10人，，这样答案不应该就是2 or 7么？？？

bqu002

Q9严重同意1楼

bqu002

16严重同意2楼的

bqu002

Q20，设只上音乐的人数为M， 只上舞蹈的为D，2个都上的为X，都不上为Y，
那么M+D+X+Y=32， M+X=15， D+X=20， Y=10，
所以M+D+X=22，推出D=7，M=2，
只上一个俱乐部的同学为M+D=9
选B