Question

The sum of 1 + 3 + 5 + 7 + 9 + 11 + 13 + 15 + 17 is
a. 7
2
c. 8
2
c. 9
2 d. 102

Answer 1

Answer:

81

Step-by-step explanation:

$number \: of \: terms = 9 \\ \\ a = 1 \: \: \: \: d = 2 \\ \\ sum = \frac{9}{2} (2 \times 1 + (8) \times 2) \\ \\ = \frac{9}{2} (2 + 16) \\ \\ = 9 \times 9 \\ = 81.$