The average of 17 numbers is 29. The average of first 9 numbers is 31 and the average of the last 9 numbers is 27. If 9th number is excluded, then what is the average of the remaining numbers?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. 29
Average = Sum of all observations/Total number of observations
The average of 17 numbers is 29
Sum of 17 numbers = 17 × 29 = 493
According to ques.
Sum of first 9 numbers = 9 × 31 = 279, Sum of last 9 numbers = 9 × 27 = 343
9th number = 343 + 279 - 493 = 29
If 9th number is excluded, then what is the average of the remaining numbers = 493 - 29 = 464/16 = 29