Question

a与b是两个两位数,它们的和为45,将a放在b的左边,组成一个4位数,则这个4位数恰好为a与b的差的504倍,求a与b

Answer 1

A+B = 45

100A + B = 504 *(A - B)

即

A+B = 45

5B = 4A

解得

A = 25

B = 20

或

A+B = 45

100A + B = 504 *(B - A)

即

A+B = 45

A = 5B

不是整数解,排除

综上A = 25 ,B = 20