The sum of first 20 odd natural numbers is

The sum of first 20 odd natural numbers is

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The sum of first n odd natural numbers is

The sum of first n odd natural numbers is

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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

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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

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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

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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

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

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

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The following series is in AP. Then find X

The following series is in AP. Then find X

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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

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Sum of n terms of the series is

Sum of n terms of the series is

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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

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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 =

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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

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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

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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

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