English Medium इयत्ता १० - CBSE Question Bank Solutions

The 9th term of an A.P. is 449 and 449th term is 9. The term which is equal to zero is

If \[\frac{1}{x + 2}, \frac{1}{x + 3}, \frac{1}{x + 5}\]  are in A.P. Then, x =

The nth term of an A.P., the sum of whose n terms is S_n, is

The common difference of an A.P., the sum of whose n terms is S_n, is

If the sums of n terms of two arithmetic progressions are in the ratio \[\frac{3n + 5}{5n - 7}\] , then their n^th terms are in the ratio

If S_n denote the sum of n terms of an A.P. with first term a and common difference dsuch that \[\frac{Sx}{Skx}\]  is independent of x, then

If the first term of an A.P. is a and nth term is b, then its common difference is

The sum of first n odd natural numbers is ______.

Two A.P.'s have the same common difference. The first term of one of these is 8 and that of the other is 3. The difference between their 30th term is

If 18, a, b, −3 are in A.P., the a + b =

The sum of n terms of two A.P.'s are in the ratio 5n + 9 : 9n + 6. Then, the ratio of their 18th term is

If \[\frac{5 + 9 + 13 + . . . \text{ to n terms} }{7 + 9 + 11 + . . . \text{ to (n + 1) terms}} = \frac{17}{16},\] then n =

The sum of n terms of an A.P. is 3n² + 5n, then 164 is its

If the nth term of an A.P. is 2n + 1, then the sum of first n terms of the A.P. is 

If 18^th and 11^th term of an A.P. are in the ratio 3 : 2, then its 21^st and 5^th terms are in the ratio

The sum of first 20 odd natural numbers is

The common difference of the A.P. is \[\frac{1}{2q}, \frac{1 - 2q}{2q}, \frac{1 - 4q}{2q}, . . .\] is 

The common difference of the A.P.

The common difference of the A.P. \[\frac{1}{2b}, \frac{1 - 6b}{2b}, \frac{1 - 12b}{2b}, . . .\] is 

If k, 2k − 1 and 2k + 1 are three consecutive terms of an A.P., the value of k is