I like this approach, but it doesn't come natural to me.

Instead I would have done \(\frac{3}{4}=\frac{x}{x+5} \\ 3x+15=4x \\ x=15\)

where x: number of boys

Girs: x+5=20

E

Hi mawus,

Ratio questions can be solved in a variety of different ways. Since the 'numbers' involved in this question are relatively simple, I'm going to show you how to use "brute force" on this question....

We're told that the ratio of boys to girls in a club is 3 to 4. This means that the number of boys MUST be a multiple of 3 and the number of girls MUST be an equivalent multiple of 4.

So, we could have....
Boys:Girls
3 and 4
6 and 8
9 and 12
12 and 16
15 and 20
18 and 24
Etc.

Notice how the number of girls gets "farther and farther away" from the number of boys as we go down the list. This pattern is important because it lets us know that each "difference" only exists in one specific example. The prompt then tells us that there are 5 MORE girls than boys. We can now find that exact situation....

It must be when there are 15 boys and 20 girls.

The question asks for the number of girls in the club.

Final Answer:

GMAT assassins aren't born, they're made,
Rich
_________________

The ratio of the number of boys to the number of girls in a certain school club is 3 to 4. If there are 5 more girls than boys in the club, how many girls are in the club?

A) 7
B) 8
C) 12
D) 15
E) 20


B/G = 3/4 & G = B+5 (or B = G-5). G = ?
(G-5)/G = 3/4
4(G-5) = 3G
4G-20 = 3G
G = 20