The average of the first four numbers is three times the fifth number. If the average of all the five numbers is 85.8, then the fifth number is:
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e 33
Explanation:
Let the fifth number be x.
The average of the first four numbers = 3x
Sum of all the first four numbers = 3x × 4 = 12x
The average of all the five numbers = 85.8
Sum of all the five numbers = 85.8 × 5 = 429
Sum of all the first four numbers + 5th number = 429
12x + x = 429
x = 429/13 = 33
∴ The 5th number is 33.