If the average of 50 numbers N1, N2, ...... N50 is M. Then the average of the numbers N1-100, N2-100,....... N50-100 will be:
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. M - 100.
Average of 50 numbers N1, N2, ...... N50 is M.
We know,
Sum = Average × Number of observations
Sum = M × 50
Sum of the new numbers = (Sum of original numbers) - (100 × Number of observations)
Sum of the new numbers = (M × 50) - (100 × 50)
Sum of the new numbers = M × 50 - 5000
Hence, New average = (M × 50 - 5000)/50
⇒ M - 100