Calculate the Average: Finding Mean of 10, 15, and 5

To solve this problem of finding the average of three numbers, follow these steps:

• Step 1: Find the sum of the numbers.
  We have the numbers 10, 15, and 5. First, calculate the sum:
  $10 + 15 + 5 = 30$.
• Step 2: Determine the number of terms.
  There are three numbers, so the number of terms is 3.
• Step 3: Calculate the average.
  Use the formula for average: $\text{Average} = \frac{\text{Sum of numbers}}{\text{Number of terms}}$.
  Plug in the sum and the number of terms:
  $\text{Average} = \frac{30}{3} = 10$.

Therefore, the average of the numbers 10, 15, and 5 is \textbf{\( 10 }\).