129.【Cynthia紫霓】Susan在银行存了x这么多钱,after the first 6months, 该账户里的钱是$2060.0, after the first year 该账户里的钱是$2121.8, 在此期间没有任何存取款活动,问这个银行的年利率是多少%?文中明确是semiannually compound A1 B2 C3 D4 E5 (E6)
204.【casperhe】五个数,算术平均数是60,后来发现有个数是错误的,replaced by 80, 平均数变为70,问原来错误的数是多少 我选的30 不知道对不对
有过一个类似的题,但是数字相对比较复杂,既不清楚,基本上都是3位数、4位数,是以表的形式给出的。
新增两题:
1. n is an integer greater than 1, the sum of n consecutive numbers is 51, what is n
A 5 B 6 C 7 D 8 E 9
2. 5 machines with the same productivity, if 4 machines work together, it will take A hours to finish a job. If put 5 machines into work, how many hours will be saved. (A是个特定的值,具体记不得了,这道还是很简单的)