The average of 11 results is 61. If the average of the first 6 results is 64 and that of the last 6 is 61, find the 6th result.

Correct option is D

Given
Average of 11 results = 61
Average of first 6 results = 64
Average of last 6 results = 61
Formula Used
Sum = Average $$\times$$​Number of items
6th result = (Sum of first 6 + Sum of last 6) - Total sum of 11 results
Solution
Total sum of 11 results = 11 $$\times$$​ 61 = 671
Sum of first 6 results = 6 $$\times$$​ 64 = 384
Sum of last 6 results = 6$$\times$$​ 61 = 366
6th result = (384 + 366) - 671
6th result = 750 - 671 = 79
Final Answer
So the correct answer is (d)

Exam Hall Method: