The average of 5 numbers is 8 and the average of last 3 numbers is The average of first two numbers will be

9
10
11
None of the above

The correct answer is (d).

The sum of the 5 numbers is 58 = 40.
The sum of the last 3 numbers is 3
9 = 27.
The sum of the first 2 numbers is 40-27 = 13.
The average of the first 2 numbers is 13/2 = 6.5.

Option (a) is incorrect because 9 is not the average of the first 2 numbers.
Option (b) is incorrect because 10 is not the average of the first 2 numbers.
Option (c) is incorrect because 11 is not the average of the first 2 numbers.