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If the nth term of an AP is (2n +1) then...

If the nth term of an AP is (2n +1) then the sum of its first three terms is

A

6n+3

B

15

C

12

D

21

Text Solution

Verified by Experts

The correct Answer is:
B
`(T_(1) +T_(2) + T_(3)) = (2 xx 1 + 1) + (2 xx 2 + 1) +(2 xx 3 +1) = 3 + 5 +7 =15`
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RS AGGARWAL-ARITHMETIC PROGRESSION-Multiple Choice Questions (Mcq)
  1. The next term of the AP sqrt(7), sqrt(28), sqrt(63),… is

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  2. If 4, x(1), x(2), x(3), 28 are in AP then x(3) = ?

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  3. If the nth term of an AP is (2n +1) then the sum of its first three te...

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  4. The sum of first n terms of an AP is (3n^(2) + 6n). The common differe...

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  5. The sum of first n terms of an AP is (5n - n^(2)). The nth term of the...

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  6. The sum of the first n terms of an A.P. is 4n^2+2n . Find the n ...

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  7. The 7th term of an AP is -1 and its 16th term is 17. The nth term of t...

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  8. The 5th term of an AP is -3 and its common difference is -4. The sum o...

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  9. The 5th term of an AP is 20 and the sum of its 7th and 11th terms is 6...

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  10. The 13^(th) term of an AP is 4 times its 3^(rd) term. If its 5^(th) te...

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  11. An AP 5, 12, 19, … has 50 terms. Its last term is

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  12. The sum of first 20 odd natural numbers is

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  13. The sum of first 40 positive integers divisible by 6 is

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  14. How many two -digit numbers are divisible by 3?

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  15. How many three-digit numbers are divisible by 9?

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  16. What is the common difference of an AP in which a(18)-a(14) = 32?

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  17. If a(n) denotes the nth term of the AP 3, 18, 13, 18,… then what is th...

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  18. Which term of the AP 72, 63, 54, … is 0?

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  19. Which term of the AP 25, 20, 15,…. Is the first negative term?

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  20. Which term of the AP 21, 42, 63, 84,.. Is 210?

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