Question

the average age of the boys in the class of 20 boys is 15.6 years what will be the average age of the find new boys come whose average age is 15.4 years. Solve it

Answer 1

sum of ages of all boys
=20×15.6
= 312
sum of ages after joining of new
boy = 15.4×21
=323.4
age of new boy = 323.4-312
=11.4