281, from 0, 1, 2, 3, 4, 5, 6, 7,8, 9 chose 3 number to form a digit. the first number of the digit can not has 0, 1, the second number can only use 0 or 1. if the second number is 0, the third number can not be 0. How many possible ways?
旧JJ:A three digit code, composed of 0-9 ,其中第一位不能为0 和1,第二位只能为0或1,且第二、三位不能同时为问有多少种不同的Code
[思路]8x2x9=144
350.某人存钱60000元部分放在A银行年利率(单利) X%, 部分放在B银行年利率 Y%(单利), 问X为多少?
1)大概讲X 与Y 之间比例关系为一比值
2)一年之后在A银行的利息比B银行的利息多多少(一数值)
[确认]c (这道题特别要说一下,因为在论坛讨论过很多次,请一定注意条件2里是amounts of interests in A…)
[确认]E
应该是C吧!!!
366.A mixture is composed of 5 gallons of water and 5 gallons of antifreezer. Now use 3 gallons of the mixture and add 3 gallons of antifreezer to the mixture. What is the percentage of antifreezer in the mixture now?
[确认] 65%
thank suse, any inputs on the rest of Qs作者: chenjing2000 时间: 2002-12-10 04:59
310. I agree with you. I think the answer should be E
366. I think the problem should be
A mixture is composed of 5 gallons of water and 5 gallons of antifreezer. Now use 3 gallons of the mixture and add 3 gallons of antifreezer to the REMAINING mixture. What is the percentage of antifreezer in the mixture now?