What is the sum of the sequence: 2+4+6+ ….. +98+100 = ?

(A) 2440
(B) 2550
(C) 2650
(D) 2700

Answer: (B) 2550

Explanation: This is an arithmetic sequence with common difference of 2. The first element is 2, the last element is 100, and total elements (from 2 to 100) are 50. So, a₁ = 2, a_n = 100, d = 2 and n = 50. So, by using the formula for the sum of n elements of an arithmetic sequence, we have