Question

Trick the average of 15 numbers is 7. If the average of the first 8 numbers be 6.5 and the average of last 8 numbers be 9.5, then the middle number is

Answer 1

Answer:

23

Step-by-step explanation:

The average of 15 numbers is 7

Hence, the sum of 15 numbers is 15 x 7 = 105

Again, the average of the first 8 numbers is 6.5

Hence, the sum of the first 8 numbers = 6.5 x 8 = 52

Also, the sum of the last 8 numbers is 9.5

Hence, the sum of the last 8 numbers = 9.5 x 8 = 76

Middle Number = (sum of the first 8 numbers + sum of the last 8 numbers) - the sum of all 15 numbers = (52 + 76) - 105 = 128 - 105 = 23