Here’s how i explain it.
a) if the no. of G has gone down, no. of B has gone up and they are now equal.
We originally had G + B = 180
We now have 7/10G = 14/10B, if we multiply both sides by 10,
7/10G = 14/10B
7G = 14B
G = 2B
This means there are half as many boys as girls. Since G + B = 180, we have 120 Girls and 60 Boys.
New no. of students = 7/10G + 14/10B = 84 + 84= 168
So no. of students has decreased
There were 180-168 = 12 less members this year
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