Correct Answer - Option 3 : 80
Given∶
Average of first 5 terminal exam = 60
Average of first 2 terminal exam = 30
Calculation∶
Sum of marks in first 5 terminal exam = 60 × 5 = 300
Sum of marks in first 2 terminal exam = 30 × 2 = 60
⇒ Sum of marks in last 3 terminal exam = 300 - 60
⇒ Sum of marks in last 3 terminal exam = 240
Average marks of last 3 terminal exam = 240/3 = 80
∴ The average of last 3 terminal exam is 80.