Correct Answer - Option 2 : 12
Given:
In a class, the average weight of students was 50 kg.
After some days 2 students left the class.
The average was decreased by 2 kg and the total weight became 480 kg.
Formula used:
Average = Sum of observations/Number of observations
Calculation:
Let the number of students be x
Total weight of students = 50x kg
After leaving of 2 students, total number of students = x - 2
Average weight now = (50 - 2) kg
⇒ 48 kg
Total weight of (x - 2) students = 48(x - 2) kg
48(x - 2) = 480
⇒ 48x = 480 + 96
⇒ 48x = 576
⇒ x = 12
∴ Total number of students before the 2 students left the class is 12