In seven given numbers, the average of the first four numbers is 4 and the last four numbers is also 4. If the average of these given seven numbers is 3, the fourth number is -

Question: In seven given numbers, the average of the first four numbers is 4 and the last four numbers is also 4. If the average of these given seven numbers is 3, the fourth number is -


Solution:
Sum of first four numbers = 4 × 4 = 16
Sum of last four numbers = 4 × 4 = 16
Sum of first four numbers and last four numbers = 16 + 16 = 32

Again, Sum of seven numbers = 7 × 3 = 21

So, fourth number is = 32 - 21 = 11