What is the sum of the first 11 terms of the AP: 17, 19, 21, …?
- A297
- B209
- C280
- D319
Show answer
Answer: (A) 297
Sₙ = n/2 [2a + (n − 1)d] = 297.
CAT Sequences & Series (AP/GP) Questions with Answers & Explanations
16 Sequences & Series (AP/GP) questions from the Quantitative Ability section of CAT, each with the correct answer and a worked explanation. Try each question first, then tap Show answer to check. When you're ready, take the timed chapter-wise test to see your all-India rank.
What is the sum of the first 6 terms of the GP: 4, 12, 36, …?
- A1452
- B1456
- C2916
- D2428
Show answer
Answer: (B) 1456
Sₙ = a(rⁿ − 1)/(r − 1) = 1456.
What is the 21st term of the AP: 1, 8, 15, …?
- A134
- B155
- C141
- D148
Show answer
Answer: (C) 141
aₙ = a + (n − 1)d = 1 + 20 × 7 = 141.
What is the sum of the first 6 terms of the GP: 1, 2, 4, …?
- A63
- B62
- C95
- D64
Show answer
Answer: (A) 63
Sₙ = a(rⁿ − 1)/(r − 1) = 63.
What is the 13th term of the AP: 19, 21, 23, …?
- A41
- B43
- C47
- D45
Show answer
Answer: (B) 43
aₙ = a + (n − 1)d = 19 + 12 × 2 = 43.
What is the sum of the first 5 terms of the GP: 1, 2, 4, …?
- A30
- B47
- C31
- D32
Show answer
Answer: (C) 31
Sₙ = a(rⁿ − 1)/(r − 1) = 31.
What is the 12th term of the AP: 8, 17, 26, …?
- A116
- B98
- C107
- D125
Show answer
Answer: (C) 107
aₙ = a + (n − 1)d = 8 + 11 × 9 = 107.
What is the sum of the first 6 terms of the GP: 4, 8, 16, …?
- A380
- B256
- C248
- D252
Show answer
Answer: (D) 252
Sₙ = a(rⁿ − 1)/(r − 1) = 252.
What is the sum of the first 26 terms of the AP: 2, 6, 10, …?
- A1350
- B1352
- C1456
- D156
Show answer
Answer: (B) 1352
Sₙ = n/2 [2a + (n − 1)d] = 1352.
What is the sum of the first 5 terms of the GP: 5, 15, 45, …?
- A1215
- B605
- C600
- D1010
Show answer
Answer: (B) 605
Sₙ = a(rⁿ − 1)/(r − 1) = 605.
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Timed Quantitative Ability test · 22 questions · instant rank
What is the sum of the first 21 terms of the AP: 3, 9, 15, …?
- A1449
- B189
- C1320
- D1323
Show answer
Answer: (D) 1323
Sₙ = n/2 [2a + (n − 1)d] = 1323.
What is the sum of the first 5 terms of the GP: 3, 9, 27, …?
- A360
- B363
- C606
- D729
Show answer
Answer: (B) 363
Sₙ = a(rⁿ − 1)/(r − 1) = 363.
What is the sum of the first 23 terms of the AP: 16, 23, 30, …?
- A2139
- B2300
- C529
- D2123
Show answer
Answer: (A) 2139
Sₙ = n/2 [2a + (n − 1)d] = 2139.
What is the sum of the first 5 terms of the GP: 5, 10, 20, …?
- A150
- B235
- C160
- D155
Show answer
Answer: (D) 155
Sₙ = a(rⁿ − 1)/(r − 1) = 155.
What is the sum of the first 28 terms of the AP: 15, 21, 27, …?
- A2688
- B588
- C2856
- D2673
Show answer
Answer: (A) 2688
Sₙ = n/2 [2a + (n − 1)d] = 2688.
What is the 26th term of the AP: 6, 11, 16, …?
- A131
- B141
- C126
- D136
Show answer
Answer: (A) 131
aₙ = a + (n − 1)d = 6 + 25 × 5 = 131.
These are RankerClub practice questions written in the CAT pattern. They are not official SSC/IBPS/RRB papers.
