Numbers & Algebra

Answer : B

Explanation :

Given numbers are 1, 3, 5.....99.
This is an A.P with a = 1, d = 2
Let it contain n terms
∴ 1 +(n-1)2 = 99
=> n = 50
Hence required sum = n/2 (first term +last term)
= 50/2(1 + 99) = 2500