Correct Answer - Option 1 : 61.4
Formula used:
Average = Sum of all observations/Total number of all observations
Calculation:
Sum of marks of 6 students = 50 × 6
⇒ 300
Sum of marks of 8 students = 70 × 8
⇒ 560
Sum of marks of 14 students = 300 + 560
⇒ 860
Average marks of 14 students = 860/14
⇒ 61.4
∴ The average marks of 14 students is 61.4