Question

the average of 11 numbers is 60. If the average of first six numbers is 58 and that of last six is 63, find the sixth number

Answer 1

Average of 11 numbers is 60

So

11 X 60 = 660

Average of first 6 numbers = 58

6X 58 = 348

So total of last 5 numbers = 660 -348 = 312

Last 6 numbers average = 63

6X 63 = 378

sixth number is 378 - 312 = 66