悉心求教小六数学题谢谢

973800qaz · 发表于 16-9-2013 21:14:27|来自：新加坡

请教各位这道题的算术方法以及设方程为男女总数的方法。麻烦大家很多次了，真是感谢各位。

If Mrs Tan transfers 1 girl from the Math Club to the English Club, 1/7 of the remaining members in the Math Club will be girls. However if she transfers 2 boys instead to the English Club ,then 1/5 of the remaining pupils in the Math Club will be girls. What is the total number of boys and girls in the Math Club?

lixin_s · 发表于 16-9-2013 21:38:42|来自：新加坡

本帖最后由 lixin_s 于 16-9-2013 21:43 编辑

G-->the number of girls left after 1 girl was moved to English Club
B-->the number of girls left after 2 boys was moved to the English club

1G+1=1B
6G-2=4B
4G+4=4B
6G-2=4G+4
6G-4G=4+2
2G-->6
G-->3
3x7=21
21+1=22The total number of boys and girls at first is 22.