These Sequences And Series Class 11 Question and Answers are most important for your upcoming examinations including JEE Main & JEE Advanced. These Sequences And Series Class 11 Question and Answers will help you to score good marks in your exams by helping you to prepare the concepts better and hence, help you to understand the concepts more clearly.

## Sequences And Series Class 11 Question and Answers

1. The arithmetic mean between 2+√(2) and 2-√(2) is

(A) 2

(B) √(2)

(C) 0

(D) 4

**Answer:** 2

2. The common difference of the sequence 5,8,11,14,… is

(A) 3

(B) −3

(C) 0

(D) 1

**Answer:** 3

3. If A, G, H are arithmetic, geometric and harmonic means between a and b respectively, then A,G,H are

(A) in G.P

(B) in A.P

(C) in H.P

(D) Real numbers

**Answer:** in G.P

4. G_{1},G_{2},…,G^{n} are said to be n geometric means between a and b if a,G_{1},…G^{n},b is

(A) a sequence

(B) not a sequence

(C) G.P

(D) A.P

**Answer:** G.P

5. The A.M between 3√(5) and 5√(5) is

(A) √(5)

(B) 2√(5)

(C) 3√(5)

(D) 4√(5)

**Answer:** 4√(5)

6. If 2/3, k, 5/8 are in AP then the value of k is

(A) 31/24

(B) 31/48

(C) 24/31

(D) 48/31

**Answer:** 31/48

7. If Sn = n3 + n2 + n + 1, where Sn denotes the sum of the first n terms of a series and Tm = 291, then m =

(A) 40

(B) 41

(C) 42

(D) 43

**Answer:** 42

8. 3, 5, 7, 9, …….. is an example of

(A) Geometric Series

(B) Arithmetic Series

(C) Rational Exponent

(D) Logarithm

**Answer:** Arithmetic Series

9. An arithmetic sequence has its 5th term equal to 22 and its 15th term equal to 62. Then its 100th term is equal to

(A) 410

(B) 408

(C) 406

(D) 404

**Answer:** 406

10. If a, b and c are in GP then

(A) b = ac

(B) b^{2} = ac

(C) b^{2} = 2ac

(D) 2b^{2} = ac

**Answer:** b^{2} = ac

11. If 1/(b + c), 1/(c + a), 1/(a + b) are in AP then

(A) a, b, c are in AP

(B) a^{2} , b^{2} , c^{2} are in AP

(C) 1/1, 1/b, 1/c are in AP

(D) None of these

**Answer:** a^{2} , b^{2} , c^{2} are in AP

12. If a_{1},a_{2}, ….. a_{n} are positive real numbers whose product is a fixed number c, then the minimum valu of a_{1} + a_{2} + … + a_{n-1} + 2a_{n} is

(A) n (2c)^{1/n }

(B) (n + 1)c^{1/n}

(C) 2n c^{1/n }

(D) (n+1)(2c)^{1/n}

**Answer:** n (2c)^{1/n }

13. If the nth term of an AP is 3n – 4, the 10th term of AP is

(A) 12

(B) 22

(C) 28

(D) 30

**Answer:** 28

14. If x, y, z are in GP and a^{x} = b^{y} = c^{z} then the value of log_{b} a * log_{b} c is

(A) 0

(B) 1

(C) -1

(D) None of these

**Answer:** 1

15. Let a, b, c form a GP of common ratio r with 0 < r < 1. If a, 2b, 3c form an AP, then r equals

(A) 1/2

(B) 1/3

(C) 2/3

(D) None of these

**Answer:** 1/3

16. The sum of n terms of the series (1/1.2) + (1/2.3) + (1/3.4) + …… is

(A) n/(n+1)

(B) 1/(n+1)

(C) 1/n

(D) None of these

**Answer:** n/(n+1)

17. The third term of a geometric progression is 4. The product of the first five terms is

(A) 4^{3}

(B) 4^{5}

(C) 4^{4}

(D) none of these

**Answer:** 4^{5}

18. Let Tr be the r th term of an A.P., for r = 1, 2, 3, … If for some positive integers m, n, we have Tm = 1/n and Tn = 1/m, then Tm n equals

(A) 1/m n

(B) 1/m + 1/n

(C) 1

(D) 0

**Answer:** 1

19. If 1/(b + c), 1/(c + a), 1/(a + b) are in AP then

(A) a, b, c are in AP

(B) a², b², c² are in AP

(C) 1/1, 1/b, 1/c are in AP

(D) None of these

**Answer:** a², b², c² are in AP

20. The sum of AP 2, 5, 8, …..up to 50 terms is

(A) 3557

(B) 3775

(C) 3757

(D) 3575

**Answer:** 3775