Sequence And Series · Mathematics · NDA

What is the remainder when $2^{120}$ is divided by 7?

If $a, b, c$ are in AP; $b, c, d$ are in GP; $c, d, e$ are in HP, then which of the following is/are correct?1. $a, c,$ and $e$ are in GP2. $\frac{1}{...

If $a, b, c$ are in HP, then what is $\frac{1}{b-a} + \frac{1}{b-c}$ equal to? 1. $\frac{2}{b}$2. $\frac{1}{a} + \frac{1}{c}$3. $\frac{1}{2} \left( \f...

If the nth term of a sequence is $\frac{2 n+5}{7}$, then what is the sum of its first 140 terms? ...

If (a + b), 2b, (b + c) are in HP, then which one of the following is correct?

Let t1, t2, t3 ... be in GP. What is $\rm \left(t_1 t_3 \ldots t_{21}\right)^{\frac{1}{11}}$ equal to ?...

What is a1 + a5 - a10 - a15 - a20 - a25 + a30 + a34 equal to ?...

What is $\displaystyle \sum_{n=1}^{34} a_n$ equal to ?

If logxa, ax and logbx are in GP, then what is x equal to ? 

If $2^{\frac{1}{c}}, 2^{\frac{b}{a c}}, 2^{\frac{1}{a}}$ are in GP, then which one of the following is correct ? 

The first and the second terms of an AP are $\frac{5}{2}$ and $\frac{23}{12}$ respectively. If nth term is the largest negative term, what is the...

In an AP, the first term is x and the sum of the first n terms is zero. What is the sum of next m terms ?

p, q, r and s are in AP such that p + s = 8 and qr = 15. What is the difference between largest and smallest numbers ?  

If G is the geometric mean of numbers 1, 2, 22, 23,.....2n-1, then what is the value of 1 + 2log2G ?

If H is the harmonic mean of numbers 1, 2, 22, 23, ......2n-1 what is n/H equal to ? 

Consider the following statements : 1. 2 + 4 + 6 + ........ + 2n = n2 + n 2. The expression n2 + n + 41 always gives a prime number for ev...

What is the ratio of the first term of A to that of B ?

What is the ratio of their 10th terms ?...

If d is the common difference of A, and D is the common difference of B, then which one of the following is always correct ?

If $\displaystyle\sum_{x=2}^n$​f(x) = 2044, then what is the value of n ?

Let x be the mean of squares of first n natural numbers and y be the square of mean of first n natural numbers. If $\frac{\text{x}}{\text{y}} = \...

If a, b, c are in GP where a > 0, b > 0, c > 0, then which of the following are correct? 1. a2, b2, c2 are in GP 2. $\frac{1}{a},...

If $\frac{a+b}{2}, b, \frac{b+c}{2}$ are in HP, then which one of the following is correct?

If the sum of the first 9 terms of an AP is equal to sum of the first 11 terms, then what is the sum of the first 20 terms ?

If the 5th term of an AP is $\frac{1}{10}$ and its 10th term is $\frac{1}{5},$ then what is the sum of first 50 terms ?...

What is the arithmetic mean of 50 terms of an AP with first term 4 and common difference 4 ?

What is the mean of the marks ?

What is the median of the marks?

What is the sum of the deviations measured from the median?