Question

一道数学题,A/B=90%,C/D=76.5%,那么（A+C)/(B+D)的答案在什么区间范围内呢?

Answer 1

A=90%B

C=76.5%D

所以A+C=90%B+76.5%D

（A+C)/(B+D)

=(90%B+76.5%D)/(B+D)

假设B=K*D (k≠0)

上式就变成

(90%KD+76.5%D)/(K+1)D

=(90%K+76.5%)/(K+1)

因为90%K