The average of seven numbers is 18. The average of first three numbers is 14 and the average of last three numbers is 19. What is the middle number
Explanation:
Total of seven numbers = 7×18 =126
Average of first three numbers = 14×3 = 42
Average of last three numbers = 19×3 =57
=42+57 = 99
Middle number is = 126-99 = 27