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Sequences and Series

JEE Main 2025 (Online) 7th April Evening ShiftMCQEasy📈 Topic in 37% papers+4−1
Ques. 1JEE Main 2025, 7 April (Evening Shift)

If the sum of the second, fourth and sixth terms of a G.P. of positive terms is 21 and the sum of its eighth, tenth and twelfth terms is 15309, then the sum of its first nine terms is :

  1. 757
  2. 755
  3. 750
  4. 760

Answer

(1) 757

Solution

Let first term = a, common ratio = r (a, r > 0).

ar + ar3 + ar5 = ar(1 + r2 + r4) = 21 ...(i)

ar7 + ar9 + ar11 = ar7(1 + r2 + r4) = 15309 ...(ii)

(ii) ÷ (i): r6 = 729 r = 3

From (i): 3a(1 + 9 + 81) = 21 273a = 21 a = 113

S9 = a(r9 - 1)r - 1 = 113 19683 - 12 = 1968226 = 757

Answer: (1)

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Ques. 2JEE Main 2025, 4 April (Morning Shift)

1 + 3 + 52 + 7 + 92 + up to 40 terms is equal to

  1. 40870
  2. 41880
  3. 43890
  4. 33980
Ques. 3JEE Main 2025, 4 April (Evening Shift)

If the sum of the first 20 terms of the series 4 14 + 3 12 + 14 + 4 24 + 3 22 + 24 + 4 34 + 3 32 + 34 + 4 44 + 3 42 + 44 + is mn, where m and n are coprime, then m + n is equal to :

  1. 423
  2. 421
  3. 422
  4. 420
Ques. 4JEE Main 2025, 4 April (Evening Shift)

Consider two sets A and B, each containing three numbers in A.P. Let the sum and the product of the elements of A be 36 and p respectively and the sum and the product of the elements of B be 36 and q respectively. Let d and D be the common differences of A.P.'s in A and B respectively such that D=d+3, d>0. If p+qp-q= 195, then p-q is equal to

  1. 540
  2. 450
  3. 600
  4. 630
Ques. 5JEE Main 2025, 3 April (Morning Shift)

Let a1, a2, a3, be a G.P. of increasing positive numbers. If a3 a5 = 729 and a2 + a4 = 1114, then 24(a1 + a2 + a3) is equal to

  1. 128
  2. 129
  3. 131
  4. 130
Ques. 6JEE Main 2025, 3 April (Morning Shift)

The sum 1 + 3 + 11 + 25 + 45 + 71 + upto 20 terms, is equal to

  1. 7240
  2. 8124
  3. 7130
  4. 6982
Ques. 7JEE Main 2025, 3 April (Evening Shift)

The sum 1 + 1 + 32! + 1 + 3 + 53! + 1 + 3 + 5 + 74! + up to terms, is equal to

  1. 3e
  2. 2e
  3. 4e
  4. 6e
Ques. 8JEE Main 2025, 2 April (Morning Shift)

Let a1, a2, a3, be in an A.P. such that k=112 a2k-1 = - 725a1, a1 0. If k=1n ak = 0, then n is :

  1. 18
  2. 17
  3. 11
  4. 10
Ques. 9JEE Main 2025, 2 April (Evening Shift)

The number of terms of an A.P. is even; the sum of all the odd terms is 24, the sum of all the even terms is 30 and the last term exceeds the first by 212. Then the number of terms which are integers in the A.P. is :

  1. 6
  2. 4
  3. 8
  4. 10
Ques. 10JEE Main 2025, 2 April (Evening Shift)

If the sum of the first 10 terms of the series 4 11 + 4 14 + 4 21 + 4 24 + 4 31 + 4 34 + is mn, where (m, n) = 1, then m + n is equal to .

Ques. 11JEE Main 2025, 29 January (Morning Shift)

Consider an A. P. of positive integers, whose sum of the first three terms is 54 and the sum of the first twenty terms lies between 1600 and 1800. Then its 11th term is :

  1. 108
  2. 90
  3. 122
  4. 84

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