Sequences & Series · NDA previous year questions

191 questions asked across 18 exam years, newest first

Year-wise papers Topic-wise questions

Practise this topic

2009 12 questions

Q62009 · 30 Aug 2009
If $x^{2}, y^{2}, z^{2}$ are in AP, then $y + z, z + x, x + y$ are
1. A.in AP
2. B.in HP
3. C.in GP
4. D.neither in AP nor in HP nor in GP
Show answer
Answer: B
Q72009 · 30 Aug 2009
Natural numbers are divided into groups as (1), (2, 3), (4, 5, 6), (7, 8, 9, 10) and so on. What is the sum of the numbers in the $1 1^{th}$ group ?
1. A.605
2. B.615
3. C.671
4. D.693
Show answer
Answer: C
Q82009 · 30 Aug 2009
If $α, β$ are the roots of $a x^{2} + b x + b = 0$ , then what is $\frac{α}{β} + \frac{β}{α} + \frac{b}{a}$ equal to ?
1. A.0
2. B.1
3. C.2
4. D.3
Show answer
Answer: A
Q92009 · 30 Aug 2009
If the roots of $a x^{2} + b x + c = 0$ are $sin α$ and $cos α$ for some $α$ , then which one of the following is correct ?
1. A. $a^{2} + b^{2} = 2 a c$
2. B. $b^{2} - c^{2} = 2 ab$
3. C. $b^{2} - a^{2} = 2 a c$
4. D. $b^{2} + c^{2} = 2 ab$
Show answer
Answer: C
Q922009 · 30 Aug 2009
If $x$ , $2 x + 2$ , $3 x + 3$ are the first three terms of a GP, then what is its fourth term ?
1. A. $- 27/2$
2. B. $27/2$
3. C. $- 33/2$
4. D. $33/2$
Show answer
Answer: A
Q1102009 · 30 Aug 2009
In an AP, the $m^{th}$ term is $1/ n$ and $n^{th}$ term is $1/ m$ . What is its $(mn)^{th}$ term ?
1. A. $1/ (mn)$
2. B. $m / n$
3. C. $n / m$
4. D.1
Show answer
Answer: D
Q1112009 · 30 Aug 2009
How many times does the digit 3 appear while writing the integers from 1 to 1000 ?
1. A.269
2. B.271
3. C.300
4. D.None of the above
Show answer
Answer: C
Q162009 · 19 Apr 2009
If the sum of the first two terms and the sum of the first four terms of a geometric progression with positive common ratio are 8 and 80 respectively, then what is the 6th term?
1. A.88
2. B.243
3. C.486
4. D.1458
Show answer
Answer: C
Q182009 · 19 Apr 2009
If $x > 1$ and $lo g_{2} x, lo g_{3} x, lo g_{x} 16$ are in GP, then what is $x$ equal to?
1. A. $9$
2. B. $8$
3. C. $4$
4. D. $2$
Show answer
Answer: A
Q312009 · 19 Apr 2009
Let $α, γ$ be the roots of $A x^{2} - 4 x + 1 = 0$ and $β, δ$ be the roots of $B x^{2} - 6 x + 1 = 0$ . If $α, β, γ, δ$ are in HP, then what are the values of $A$ and $B$ respectively?
1. A. $3, 8$
2. B. $- 3, - 8$
3. C. $3, - 8$
4. D. $- 3, 8$
Show answer
Answer: A
Q322009 · 19 Apr 2009
Under which one of the following conditions does the system of equations $k x + y + z = k - 1$ , $x + k y + z = k - 1$ , $x + y + k z = k - 1$ have no solution?
1. A. $k = 1$
2. B. $k \neq = - 2$
3. C. $k = 1 or k = - 2$
4. D. $k = - 2$
Show answer
Answer: D
Q332009 · 19 Apr 2009
If the sides of a triangle are 6 cm, 10 cm and 14 cm, then what is the largest angle included by the sides?
1. A. $9 0^{\circ}$
2. B. $12 0^{\circ}$
3. C. $13 5^{\circ}$
4. D. $15 0^{\circ}$
Show answer
Answer: B