请教两道数学题

littlestoner

1. A certaincompany retirement plan has a "rule of 70" provision that allows an employee to retire when the employee's age plus year of employment with the company total at least 70. In what year could a female employee hired in 1986 on her 32nd birthday first be eligible to retire under this provision?

这是OG上的题,答案是2005年. 解释上是画表做出来的, 挺花时间, 请问什么方法做比较快算出答案?

2. 5^21*4^11=2*10^n  问N的值.  请问如何算呢?

谢谢!

CasualWalker

2, 5^21*4^11=5^21*2^22=10^21*2

so,n=21

1, 设该雇员被雇用后X年后退休. 则:

(32+x)+x=70

x=19

so, 应该为 1986+19=2005年

littlestoner

谢谢！！