The average of 37 number is 49. The average of the first 21 numbers is 43.8 and that of the last 17 numbers is 55.6. If the 21st number is excluded, then what is the average of the remaining numbers (correct to one decimal place)?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 48.9
Sum of the 37 numbers = 37 × 49 =1813
Sum of the first 21 numbers = 21 × 43.8 = 919.8
Sum of the last 17 numbers = 17 × 55.6 = 945.2
So, the 21st number = (919.8 + 945.2) - 1813 = 52
So, average of 36 numbers = (1813 - 52)/36 = 48.91