Average mark in a class test of 40 students is 40. Average mark of all the 25 boys is 46. Then the average mark obtained by the girls is

Question: Average mark in a class test of 40 students is 40. Average mark of all the 25 boys is 46. Then the average mark obtained by the girls is

Solution:
Given,
Average mark of 40 students = 40
Total mark of 40 students = (40 × 40)
= 1600

Average mark of all the 25 boys = 46
Total mark of all the 25 boys = (46 × 25)
= 1150

∴ Total marks of all the 15 girls is (1600 - 1150) = 450

So the average mark of 15 girls = 450/15 = 30