The mean of twelve positive numbers is 3. When another number is added, the mean becomes 5. Find the thirteenth number
-
29
- 26
- 25
- 24
The correct answer is: A
Explanation
Let the sum of the 12 numbers be x and the 13th number be y.
\(\frac{x}{12} = 3 \implies x = 36\)
\(\frac{36 + y}{13} = 5 \implies 36 + y = 65\)
\(y = 65 - 36 = 29\)