Question

Sum of odd numbers from 1 to 100?

Answer 1

Series would be: 1,3,5......99

Here, a=1, d = 3-1 = 2, l = 99

l = a+(n-1)d

99 = 1+(n-1)2

98 = 2n-2

2n = 100

n = 50

Sum would be Sn = n/2 (a+l)

 50/2 (1+99)

 25(100) = 2500

So, your answer is 2500