Question 1201509
<font color=black size=3>
Answer: <font color=red size=4>135</font>



Work Shown:


x = number of girls initially
2x = number of boys initially


40 boys leave
2x becomes 2x-40


15 girls leave
x becomes x-15


"<font color=blue>number of girls who remained was 3/5 of the number of boys who remained in the club</font>" tells us that
x - 15 = (3/5)*(2x-40)
5(x - 15) = 3(2x-40)
5x - 75 = 6x-120
5x-6x = -120+75
-x = -45
x = 45 girls initially
which leads to
2x = 2*45 = 90 boys initially


45+90 = <font color=red>135</font> is the final answer.


---------

Check:
90 boys at first
40 boys leave
90-40 = 50 boys left


45 girls at first
15 girls leave
45-15 = 30 girls left
ratio of girls remaining to boys remaining is 30/50 = 3/5, which confirms the answer is correct.
</font>