A class of 30 students appeared in a test. The average score of 12 students is 60, and that of the rest is 60. What is the average score of the class?

Correct option is A

Given:

Total students = 30

Average of 12 students = 60

Average of remaining 18 students = 60

Formula Used:

​$$\text{Average} = \frac{\text{Sum of all observations}}{\text{Number of observations}}$$​​

Solution:
Total sum$$=12\times60+18\times60=(12+18)\times60=30\times60$$​​
Class average =$$\frac{30\times60}{30}=60$$​​