3 to 4 boys in a math class if there are 12 boys how many girls are there

Question

I just need to know  if im right

Answer 1

I think you mean 3 girls to 4 boys. Anyways, gonna shorthand girls to g and boys to b, just to save space.

So our ratio looks like:

^{3 g} / _{4 b} = ^x / _{12 b}

Multiply both sides by 12 boys:

^{3 g * 12 b} / _{4 b} = x

Factor out 4, and cancel out boys:

3 girls * 3 = x

9 girls = x

So there are 9 girls in the class.