Question

Mean marks of 60 students of a class are 63 and that of 40 other students are 60. The mean marks of all taken together are
1. 61.8
2. 61.5
3. 62
4. None of these

Answer 1

Correct Answer - Option 1 : 61.8

Given 

Mean marks of 60 student = 63

Mean marks of 40 other student = 60 

Formula Used 

Average = (sum of observation)/No. of observation 

Calculation 

Total marks by all student = 63 × 60 + 40 × 60 = 6180 

Average marks of all 100 students = 6180/100 = 61.8

∴ The required answer is 61.8