The average of 52 numbers is 48.5. The average of the first 22 numbers is 59.8 and that of the last 32 numbers is 41.7. If the 21st and 22nd numbers are excluded, then what is the average of the remaining numbers?
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. 47.88.
Sum of all numbers = 52 × 48.5 = 2522
Sum of first 22 numbers = 22 × 59.8 = 1315.6
Sum of last 32 numbers = 32 × 41.7 = 1334.4
Sum of 21st and 22nd numbers = 1315.6 + 1334.4 - 2522 = 128
Sum after 21st and 22nd numbers exclusion = 2522 - 128 = 2394
Remaining numbers = 52 - 2 = 50
New average = 2394/50 = 47.88