The average of 9 numbers is 63. If the average of the first 4 numbers is 60 and the average of the last 4 numbers is 66, what is the fifth number?
Show answer & explanation
Correct answer: A
Explanation
Given:
Average of 9 numbers = 63
Average of first 4 numbers = 60
Average of last 4 numbers = 66
Total sum of 9 numbers = 63 × 9 = 567
Sum of first 4 numbers = 60 × 4 = 240
Sum of last 4 numbers = 66 × 4 = 264
Fifth number = 567 − (240 + 264) = 63
Fifth number = 63