Question

Sum of all terms of the series -3, -1, 3, 5.... 51 is

Answer 1

Given:

-3, -1, 3, 5 ...... 51

a = -3

d = -1 - (-3) = -1 + 3 = 2

an = 51

an = a + (n - 1)*d

51 = -3 + (n - 1)*2

54 = (n - 1)*2

n - 1 = 27

n = 28

Sn = (n/2)*(a + an)

Sn = (28/2)*(-3 + 51)

Sn = 14 * 48

Sn = 672 ——> Answer