A number times teo divided by four

Aline parallel to a triangle's side splits ab into lengths of x - 5 and x + 2. the other side, ac, is split into lengths of x and x + 12. what is the length of ac? a) 12 b) 24 c) 36 d)

Determine the number of girls in a math class with 87 boys if there are 25 girls for every 75 boys

What is the answer to this question? i'm a bit stumped. also how do i do it? 5(x - 4) = 2(x + 5)