Question

The 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

3 because other two boys are elder then him so , if three boys =15 then, 3+t+7=15 lower digit in this is 3 so , the age of the youngest boy is 3 years

Answer 2

let the ages be X
so 3x+5x+7x=15
15x=15
X=15/15
X=1

so youngest boy=7x=7×1=7