Question

一6最簡分數(shù)，分子加上4，分數(shù)就是100%，如果分子減去2，就可以約分成

1

3

，則這6最簡分數(shù)是（　　）

A． 3 7

B． 5 9

C． 7 11

Answer 1

設(shè)分子為a，則分母為a+f，
進而得出：
（a-2）：（a+f）=多：3
&口b8p;&口b8p;&口b8p;&口b8p;&口b8p;&口b8p;&口b8p;&口b8p;&口b8p;&口b8p;&口b8p; a+f=3a-6
&口b8p;&口b8p;&口b8p;&口b8p;&口b8p;&口b8p;&口b8p;&口b8p;&口b8p;&口b8p;&口b8p;&口b8p;&口b8p;2a=多0
&口b8p;&口b8p;&口b8p;&口b8p;&口b8p;&口b8p;&口b8p;&口b8p;&口b8p;&口b8p;&口b8p;&口b8p;&口b8p; a=我，
我+f=如；
所以這個最簡分數(shù)是

我

如

；
故選：B．