Question

The average of all positive even integers less than or equal to 40 is___.

Answer 1

Correct Answer: 21

To find the average of all positive even integers less than or equal to 40, we first identify these numbers: 2, 4, 6, ..., 40. This sequence is an arithmetic sequence where: First term (a1) = 2, Last term (an) = 40, Common difference (d) = 2. To find the number of terms (n), use the formula for the n-th term of an arithmetic sequence: an = a1 + (n-1)×d. 40 = 2 + (n-1)×2 40 - 2 = 2(n-1) 38 = 2(n-1) 19 = n-1 n = 20 The average of an arithmetic sequence can be calculated by the formula: Average = (a1 + an) / 2. Average = (2 + 40) / 2 = 42 / 2 = 21. Thus, the average of all positive even integers less than or equal to 40 is 21