Question

He average age of three boys is 15 years. If their ages are in ratio 3:5:7, the age of the youngest boy is

Answer 1

let the ages be 3x 5x and 7x

so 3x +5x+ 7x/3 =15

15x=15*3

15x=75

x=5

the youngest of all is 3x =3*5=

15 years