Question

A mathematics club consisted of 40 members. 70% of the members were girls. After some members joined the club, 60% of the members are girls.
if the new members consist of 6 more boys than girls, how many members in total are boys.

According to answer key, the answer should be 20 boys, but I do not get how to solve that.

Answer 1

Answer:

Thus 8 of the new members were boys, so there are 12+8 = 20 total boys in the club.

Step-by-step explanation:

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Answer 2

Answer:

40⋅0.70=28 girls in the club, which means there must be 12 boys in the club.

Let’s define a variable b to be the number of new members that are boys. W know that there are b−6 new members that are girls, so, 2b−6 new members in total.

12+b/2b−6+40=0.4 .

Multiplying both sides by 2b+34, we have that 12+b=0.8b+13.6.

Therefore 0.2b=1.6, so b=8.

Thus 8 of the new members were boys, so there are 12+8 = 20 total boys in the club.

I hope you understood the answer.