求救！！Prep 2道数学题！ 谢谢！

mudiduanger

1.DS:  is the thre-digit number n<=550
条件1. the product of the digits in n is 30
条件2.  the sum of digit in n is 10

答案是C， 我的算法是条件1推出：xyz=30  2推出：x+y+z=10  但我觉得1、2推不出 100x+10y+z<=550.




2. Bobby bought two share of stock, which sold for 96 each.   If he had profit of 20% on the sale of the shares but a loss of 20% on the sale of the other share, then on the sale of both shares combined b bobby had.

答案是   the loss of 8,        我选的是 no loss, no profit.  我知道我选的错了，可是就是算不出the loss of 8.



大家帮帮忙吧！！！谢谢！！！

mudiduanger

谢谢大家解答，明白了！！祝好运！

jingjane222

第２题

0.96=1.2*X1  X1=0.8 (Share 1 with 20% gain)
0.96=0.8*X2  X2=1.2 (Share 2 with 20% loss)

X1+X2=2.00 (original price paid)
0.96*2=1.92 (price sold)

Loss 应该是 8 cents or 4%

wangliming

two share of stock......share应该有s吧

MarilynR

第一题
条件一可得 三个数字为 1，5，6 或者 2，5，3 ，不充分
条件二 单独不充分 两者结合可得 三个数字为 2，5，3， 任意组合 《=550

第二题能不能把原题 原样子打出来？