Out of four numbers, the average of first three is 15 and

Home » Aptitude » Average » Question

Out of four numbers, the average of first three is 15 and that of last three is 16. If the last number is 19, find the first number.

1. 14
2. 15
3. 16
4. 18

Correct Option: C

Here , The last number = 19
The average of first three = 15
Sum of all four numbers = 3 × 15 + 19 = 64
The average of last three = 16
Sum of last three numbers = 3 × 16 = 48
So, first number = 64 – 48 = 16