Question 21
ProgressionsFind the sum of the first 18 terms of the series 3, 6, 9, ..., 36.
- A.505
- B.513
- C.433
- D.635
Show the answer and explanation
Answer: B (513)
Explanation
a = 3, d = 3: S18 = 18/2 × (6 + 17 × 3) = 9 × 57 = 513.
Find the sum of the first 18 terms of the series 3, 6, 9, ..., 36.
Answer: B (513)
a = 3, d = 3: S18 = 18/2 × (6 + 17 × 3) = 9 × 57 = 513.