The average of 9 numbers arranged in ascending order is 18. If the average of the first five numbers is 16 and the average of the last five numbers is 19, then what is the fifth number?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 13.
Sum of 9 numbers = 9 × 18 = 162
Sum of first 5 numbers = 5 × 16 = 80
Sum of last 5 numbers = 5 × 19 = 95
Fifth number = (80 + 95) - 162
⇒ 175 - 162 = 13