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

Q: What's the difference between average and sum?

The sum is just adding all numbers together (10 + 15 + 5 = 30). The average is that sum divided by how many numbers you have (30 ÷ 3 = 10).

Q: Why do I divide by 3 and not some other number?

You divide by 3 because there are exactly 3 numbers in this problem: 10, 15, and 5. Always count how many values you're averaging!

Q: What if the numbers don't divide evenly?

That's okay! Your average can be a decimal or fraction. For example, if you had numbers that sum to 31, the average would be $ \frac{31}{3} = 10.33... $

Q: Can I check my answer a different way?

Yes! Think about it logically: 10 is between our smallest (5) and largest (15) numbers, and it's closer to the middle values. This makes sense as an average!

Q: Does the order of the numbers matter?

No! You can add 5 + 10 + 15 or 15 + 5 + 10 - you'll always get the same sum (30) and the same average (10).

Average Calculation with Three Numbers

Calculate the average

of $10$ , $15$ , and $5$ .

❤️ Continue Your Math Journey!

We have hundreds of course questions with personalized recommendations + Account 100% premium

Step-by-step video solution

Watch the teacher solve the problem with clear explanations

00:00 Calculate the average

00:03 To calculate the average, we need to divide the sum by the number of occurrences

00:07 Let's sum up the numbers

00:12 and divide by the number of occurrences (3)

00:29 and this is the solution to the question

Step-by-step written solution

Follow each step carefully to understand the complete solution

Understand the problem

Calculate the average

of $10$ , $15$ , and $5$ .

Step-by-step solution

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 }$$ .

Final Answer

Key Points to Remember

Essential concepts to master this topic

Formula: Average = Sum of numbers ÷ Number of terms
Technique: Add all values first: 10 + 15 + 5 = 30
Check: Multiply answer by count: 10 × 3 = 30 (matches our sum) ✓

Common Mistakes

Avoid these frequent errors

Forgetting to divide by the number of terms
Don't just add the numbers and stop at 30 = wrong answer! This gives you the sum, not the average. Always divide the sum by how many numbers you added together.

Practice Quiz

Test your knowledge with interactive questions

Calculate the average of $$ 10 $$ and $$ 12 $$ .

FAQ

Everything you need to know about this question

What's the difference between average and sum?

The sum is just adding all numbers together (10 + 15 + 5 = 30). The average is that sum divided by how many numbers you have (30 ÷ 3 = 10).

Why do I divide by 3 and not some other number?

You divide by 3 because there are exactly 3 numbers in this problem: 10, 15, and 5. Always count how many values you're averaging!

What if the numbers don't divide evenly?

That's okay! Your average can be a decimal or fraction. For example, if you had numbers that sum to 31, the average would be $\frac{31}{3} = 10.33...$

Can I check my answer a different way?

Yes! Think about it logically: 10 is between our smallest (5) and largest (15) numbers, and it's closer to the middle values. This makes sense as an average!

Does the order of the numbers matter?

No! You can add 5 + 10 + 15 or 15 + 5 + 10 - you'll always get the same sum (30) and the same average (10).

🌟 Unlock Your Math Potential

Get unlimited access to all 18 Data Exploration questions, detailed video solutions, and personalized progress tracking.

📹

Unlimited Video Solutions

Step-by-step explanations for every problem

📊

Progress Analytics

Track your mastery across all topics

🚫

Ad-Free Learning

Focus on math without distractions

No credit card required • Cancel anytime