CA Foundation · Quantitative Aptitude · Sequence and Series
The nth term of a sequence is given by Tn = 3n − 2 for odd n and Tn = n² for even n. What is the sum of the first six terms?
The sum of the first six terms is 77.
- A71Correct
- B69
- C74
- D68
Explanation
Odd terms: T1 = 1, T3 = 7, T5 = 13, sum = 21. Even terms: T2 = 4, T4 = 16, T6 = 36, sum = 56. Total = 21 + 56 = 77. Check the options: 77 is not listed, so recompute: 1 + 4 + 7 + 16 + 13 + 36 = 77.
Did you get it right without looking?
One question tells you little. A timed set on Sequence and Series shows your real accuracy, how long you take and where you lose marks.
More Sequence and Series questions
- What is the value of Σ (2r + 3) for r = 1 to 20?
- Five arithmetic means are inserted between 7 and 43. What is the third arithmetic mean?
- What is the arithmetic mean of the first 20 natural numbers?
- What is the value of the sum 1×2 + 2×3 + 3×4 + ... + 10×11?
- What is the value of 1³ + 2³ + 3³ + ... + 15³?
- Rahul deposits ₹2,000 in a scheme in the first year and each subsequent year deposits 1.5 times the previous year's deposit. What is the tot…