What is sum of the first 12 numbers of the series: 2 , 6, 10, 14, …?

(A) 260
(B) 268
(C) 280
(D) 288

The answer is: (D) 288
Solution
This is an arithmetic sequence with common difference of 4. The first element is 2, and total elements are 12. So, a1 = 1, d = 3 and n = 12. So, by using the formula of nth term of an arithmetic sequence, first we will find the 12th term

What is |2|-|-2|-22-(-2)2=?

Q. What is: |2| – |–2| – 22 – (–2)2 = ?
(A) –8
(B) –6
(C) –4
(D) –2

The answer is: (A) –8
Solution

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

(A) 2450
(B) 2500
(C) 2550
(D) 2600

The answer is: (C) 2550
Solution
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, an = 100, d = 2 and n = 50. So, by using the formula for the sum of n elements of an arithmetic sequence, we have