Question

Which of the following represents the sum of the series below?

the sum of the first 7 odd numbers
the sum of the first 7 even numbers
the sum of the 7 numbers beginning with 2
the sum of the 7 numbers beginning with 1

Answer 1

The correct answer is A. The sum of the first 7 odd numbers

Explanation:

1. Let's review the information provided to us for solving the sum of the series:

Sₙ = ∑ ⁷ k = 1, [ 1 + (k -1) (2)]

2. Let's resolve the sum of the series:

For k = 1, [ 1 + (1 -1) (2)] = [1 + 0 * 2] = [1 + 0] = 1

For k = 2, [ 1 + (2 -1) (2)] = [1 + 1 * 2] = [1 + 2] = 3

For k = 3, [ 1 + (3 -1) (2)] = [1 + 2 * 2] = [1 + 4] = 5

For k = 4, [ 1 + (4 -1) (2)] = [1 + 3 * 2] = [1 + 6] = 7

For k = 5, [ 1 + (5 -1) (2)] = [1 + 4 * 2] = [1 + 8] = 9

For k = 6, [ 1 + (6 -1) (2)] = [1 + 5 * 2] = [1 + 10] = 11

For k = 7, [ 1 + (7 -1) (2)] = [1 + 6 * 2] = [1 + 12] = 13

The correct answer is A. The sum of the first 7 odd numbers