The average of 11 numbers arranged in an order is 41. The average of the first five numbers is 18 and that of the last five numbers is 64. What is the sixth number?

Correct option is D

Given:

Average of 11 numbers = 41

Average of first five = 18

Average of last five = 64

Formula Used:

​$$Average = \frac{Sum\ of \ observations}{Number \ of \ observations}$$​​

Solution:

Total of 11 numbers = 11$$\times$$​ 41 = 451

Total of first five numbers = 5 $$\times$$​18 = 90

Total of last five numbers = 5 $$\times$$​ 64 = 320

Total of 10 numbers = 90 +320 = 410

Now total of 11 numbers = Total of first 5 numbers + Total of last five numbers + Sixth number

Then Sixth number = 451 - 410 = 41