The average of 11 numbers is 50. If the first six numbers have an average of 49 and the last six numbers have an average of 52, find the middle number.
Show answer & explanation
Correct answer: B
Explanation
Given:
Average of 11 numbers = 50
Average of first 6 numbers = 49
Average of last 6 numbers = 52
Total sum of 11 numbers = 11 × 50 = 550
Sum of first 6 numbers = 6 × 49 = 294
Sum of last 6 numbers = 6 × 52 = 312
Middle number = 294 + 312 − 550 = 606 − 550 = 56