Question

The average of 11 numbers is 63,that of first 6 numbers is 60,and that of last 6 numbers is 65,find the 6th number

Answer 1

Find the sum of 11 numbers:

Average of 11 numbers = 63

Sum of the 11 numbers = 63 x 11 = 693

.

Find the sum of the first 6 numbers:

Average of the 6 numbers = 60

Sum of the 6 numbers = 60 x 6 = 360

.

Find the sum of the last 6 numbers:

Average of the 6 numbers = 65

Sum of the 6 numbers = 65 x 6 = 390

.

Find the 6th number:

The 6th number is the overlapping number between the first six and the last six. Therefore the 6th number is computed in both sets.

Sum of the first 6 and the last 6 = 360 + 390 = 750

6th number = 750 - 693 = 57

.

Answer: The 6th number is 57.