Correct Answer - Option 1 : 45
Given∶
Average of 6 numbers = 20
If one number excludes, the average reduced by 5
Formula Used∶
Sum of observations = Average × Number of Observations
Excluded observation = [Sum of x observation – Sum of (x – 1) observation)
Calculation∶
Average of 6 numbers = 20
Sum of 6 numbers = 20 × 6 = 120
Average of remaining 5 numbers = 20 – 5 = 15
Sum of remaining 5 numbers = 15 × 5 = 75
So, excluded number = [sum of 6 numbers – sum of 5 numbers] = 120 – 75 = 45
∴ The excluded number is 45.
