Sequences and Series
462 Questions
Start JEE Mains Test
1985
Q451
JEE Advanced
MCQ
14 Mar 2026
If $a,\,b,\,c$ are in GP., then the equations $\,\,\alpha {x^2} + 2bx + c = 0$ and $d{x^2} + 2ex + f = 0$ have a common root if ${d \over a},\,{e \over b},{f \over c}$ are in ________.
A.
A.P.
B.
GP.
C.
H.P.
D.
none of these
1985
Q452
JEE Advanced
Numerical
14 Mar 2026
Find the sum of the series :
$$\sum\limits_{r = 0}^n {{{\left( { - 1} \right)}^r}\,{}^n{C_r}\left[ {{1 \over {{2^r}}} + {{{3^r}} \over {{2^{2r}}}} + {{{7^r}} \over {{2^{3r}}}} + {{{{15}^r}} \over {{2^{4r}}}}..........up\,\,to\,\,m\,\,terms} \right]} $$
Correct Answer: $${{{2^{mn}} - 1} \over {{2^{mn}}\left( {{2^n} - 1} \right)}}$$
1984
Q453
JEE Advanced
Numerical
14 Mar 2026
If $n$ is a natural number such that
$n = {p_1}{}^{{\alpha _1}}{p_2}{}^{{\alpha _2}}.{p_3}{}^{{\alpha _3}}........{p_k}{}^{{\alpha _k}}$ and ${p_1},{p_2},\,\,......,\,{p_k}$ are distinct primes, then show that $In$ $n \ge k$ $in$ 2
$n = {p_1}{}^{{\alpha _1}}{p_2}{}^{{\alpha _2}}.{p_3}{}^{{\alpha _3}}........{p_k}{}^{{\alpha _k}}$ and ${p_1},{p_2},\,\,......,\,{p_k}$ are distinct primes, then show that $In$ $n \ge k$ $in$ 2
Correct Answer: Solve it.
1984
Q454
JEE Advanced
Numerical
14 Mar 2026
If $a > 0,\,b > 0$ and $\,c > 0,$ prove that $\,c > 0,$ prove that $\left( {a + b + c} \right)\left( {{1 \over a} + {1 \over b} + {1 \over c}} \right) \ge 9$
Correct Answer: Solve it.
1984
Q455
JEE Advanced
Numerical
14 Mar 2026
The sum of integers from 1 to 100 that are divisible by 2 or 5 is ............
Correct Answer: 3050
1983
Q456
JEE Advanced
MCQ
14 Mar 2026
The rational number, which equals the number $2\overline {357} $ with recurring decimal is
A.
${{2355} \over {1001}}$
B.
${{2379} \over {997}}$
C.
${{2355} \over {999}}$
D.
none of these
1983
Q457
JEE Advanced
Numerical
14 Mar 2026
Find three numbers $a,b,c$ between $2$ and $18$ such that
(i) their sum is $25$
(ii) the numbers $2,$ $a, b$ are consecutive terms of an A.P. and
(iii) the numbers $b,c,18$ are consecutive terms of a G.P.
(i) their sum is $25$
(ii) the numbers $2,$ $a, b$ are consecutive terms of an A.P. and
(iii) the numbers $b,c,18$ are consecutive terms of a G.P.
Correct Answer: $$5, 8, 12$$
1982
Q458
JEE Advanced
MCQ
14 Mar 2026
The third term of a geometric progression is 4. The product of the first five terms is
A.
43
B.
45
C.
44
D.
none of these
1982
Q459
JEE Advanced
MCQ
14 Mar 2026
If $x,\,y$ and $z$ are $pth$, $qth$ and $rth$ terms respectively of an A.P. and also of a G.P., then ${x^{y - z}}\,{y^{z - x}}\,{z^{x - y}}$ is equal to :
A.
$xyz$
B.
$0$
C.
$1$
D.
None of these
1982
Q460
JEE Advanced
Numerical
14 Mar 2026
Does there exist a geometric progression containing $27, 8$ and $12$ as three of its terms? If it exits, how many such progressions are possible ?
Correct Answer: $$ \Rightarrow $$ yes infinite
1980
Q461
JEE Advanced
Numerical
14 Mar 2026
The interior angles of a polygon are in arithmetic progression. The smallest angle is ${120^ \circ }$, and the common difference is ${5^ \circ }$, Find the number of sides of the polygon.
Correct Answer: 9
1979
Q462
JEE Advanced
Numerical
14 Mar 2026
The harmonic mean of two numbers is 4.Their arithmetic mean $A$ and the geometric mean $G$ satisfy the relation. $2A + {G^2} = 27$
Correct Answer: $$3$$ and $$6$$ or $$6$$ and $$3$$