Question

There are 2 boys for every 3 girls. Today 5 new boys were added making the number of girls and boys the same. How many boys and girls were there originally?

Answer 1

10 boys, 15 girls

Explanation:

Original ratio: 2 boys/3 girls

let x be the scale factor of the ratio

2x plus 5 boys over 3x girls = 1 (because the # of boys/girls are the same)-------> 2x+5/3x = 1

Simplify: 2x+5=3x

Simplify: 5=x

plug x back into the original ratio: 10/15

Check: 10/15 = 2/3

10 boys + 5 boys = 15, 15/15 = 1