Question

The average age of boys in a class of 30 is 15 years. If 10 more boys join the




class, the average of the whole class gets reduced by a year. What is the average age of




newcomers? [this mixes age and average

Answer 1

hi

Total Student -year for 40 students =40*15=600.

when 10 new students were admitted the avg. increased by 0 .2 or becomes 15.2 years.

Therefor new Student-year for 50 students=15.2*50=760.

Student-year for 40 students 600 & for 50 students its 760, difference = 160.

hence we can say that 160 student-years were added, which is of 10 student.

Hence the average for 10 new students = 160/10 or 16 years .

hope it will help you