In a class, 50% of the male students and 2/3 of the female students speak French. If there are ¾ as many girls as boys, what fraction of the entire class speaks French?

x=# of boys in the class y=# of students that speak French

Therefore we are looking for y / (total number in class). But the total number in the class is boys plus girls, so x + 3/4x=7/4x The 3/4 is because they told us there are 3/4 as many girls as boys. So now

y / (total number in class) = y / (7/4x)

Now we know that the number of students that speak French are: 1/2 boys +2/3 girls or 1/2x + 2/3(3/4x) = y = 1/2x + 6/12x = x Therefore y / (7/4x) = x / (7/4)x = 4/7

So the curve ball here is that the number that speak French just happens to be equal to the number of boys in the class, and boys make up 4/7 of the class as well.