Question

The first term of an A.P. is 2 and common difference is 4. The sum of its 40 terms will be

• A. 3200
• B. 1600
• C. 200
• D. 2800

Answer 1

Answer: (A)

3200

Answer 2

$S = \frac{n}{2}\lbrack 2a + (n - 1)d\rbrack = \frac{40}{2}\lbrack 2 \times 2 + (40 - 1)4\rbrack = 3200$