Step 1: Write down the numbers we have: 7, 9, 11, 13, and x.
Step 2: Count how many numbers there are. We have 5 numbers (7, 9, 11, 13, and x).
Step 3: The mean (average) is given as 10.
Step 4: To find the mean, we add all the numbers together and divide by how many numbers there are. So we set up the equation: (7 + 9 + 11 + 13 + x) / 5 = 10.
Step 5: First, add the numbers we know: 7 + 9 + 11 + 13 = 40.
Step 6: Now, substitute 40 into the equation: (40 + x) / 5 = 10.
Step 7: To eliminate the division, multiply both sides of the equation by 5: 40 + x = 10 * 5.
Step 8: Calculate 10 * 5, which equals 50. So now we have: 40 + x = 50.
Step 9: To find x, subtract 40 from both sides: x = 50 - 40.
Step 10: Calculate 50 - 40, which equals 10. So, x = 10.
