The sum of first 20 odd natural numbers is
The sum of first 20 odd natural numbers is
The sum of first n odd natural numbers is
The sum of first n odd natural numbers is
The number of terms of the A.P. 3, 7, 11, 15, ... to be taken so that the sum is 406 is
The number of terms of the A.P. 3, 7, 11, 15, ... to be taken so that the sum is 406 is
The sum of n terms of two A.P.'s are in the ratio 5n + 9 : 9n + 8. Then, the ratio of their 18th term is
The sum of n terms of two A.P.'s are in the ratio 5n + 9 : 9n + 8. Then, the ratio of their 18th term is
If the first term of an A.P. is a and nth term is b, then its common difference is
If the first term of an A.P. is a and nth term is b, then its common difference is
If the sum of P terms of an A .P. is q and the sum of q terms is p, then the sum of p + q terms will be
If the sum of P terms of an A .P. is q and the sum of q terms is p, then the sum of p + q terms will be
If 18, a,b,-3 are in A,P., the a + b =
If 18, a,b,-3 are in A,P., the a + b =
The following series is in AP. Then find X
The following series is in AP. Then find X
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 terms 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 terms is
Sum of n terms of the series is
Sum of n terms of the series is
In an AP, Sp = q,Sq = p and Sr denotes the sum of first r terms. Then, Sp + q is equal to
In an AP, Sp = q,Sq = p and Sr denotes the sum of first r terms. Then, Sp + q is equal to
If the sum of first n even natural numbers is equal to k times the sum. of first n odd natural numbers, then k =
If the sum of first n even natural numbers is equal to k times the sum. of first n odd natural numbers, then k =
The 9th term of an A.P. is 449 and 449th term is 9. The term which is equal to zero is
The 9th term of an A.P. is 449 and 449th term is 9. The term which is equal to zero is
If the first term of an A.P. is 2 and common difference is 4, then the sum of its 40 terms is
If the first term of an A.P. is 2 and common difference is 4, then the sum of its 40 terms is
If 18th and 11th term of an A.P. are in the ratio 3 : 2, then its 21st and 5th terms are in the ratio
If 18th and 11th term of an A.P. are in the ratio 3 : 2, then its 21st and 5th terms are in the ratio