First 79 natural numbers: Using mean properties of a sequence from 1 to 79, determine the average value.

Introduction / Context:
For consecutive natural numbers from 1 to n, the average is the midpoint between the first and the last term. This is a standard property of arithmetic progressions.

Given Data / Assumptions:

• Sequence: 1, 2, 3, ..., 79
• Count = 79

Concept / Approach:
Average of an arithmetic progression = (first + last) / 2. This exploits symmetry around the center term for an odd count.

Step-by-Step Solution:

Verification / Alternative check:
Since there are 79 terms, the middle (40th) term is 40. For an odd count the median equals the mean in an arithmetic progression.

Why Other Options Are Wrong:

• 39, 39.5, 40.5, 79: do not match the AP mean formula for 1 to 79.

Common Pitfalls:
Using n/2 incorrectly or confusing median with mean when the count is even. Here both coincide at 40 due to odd length and symmetry.

Final Answer:
40