Question 696902
Ages of 10 boys= 12
Ages of 12 boys= 12.5
Ages of remaining(18 boys)= 13
Average age of boys= age of each boy/total no. of boys
That is, (10x12   12x12.5   18x13)/40
= (120 150 234)/40
= 504/40
= 12.6
The avg age of boys is 12.6 yrs