the ratio of boys to girls

Question

The ratio of boys to girls in a class is 3:2. There are 15 boys in the class. How many total boys and girls are in the class? 

Answer 1

n = total number of boys and girls

 

15 boys at 3/2 boys to girls ratio ⇒

 

[3/(3 + 2)]n = 15

 

n = 15(5/3) = 25

 

Number girls:  n - 15 = 25 - 15 = 10

Number of boys:  15

Total number of boys and girls:  25

 

Note that 15/10 = 3/2.