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Let a₁, a₂, a₃, be an A.P, such that a₁+a₂+ +a_p a₁+a₂+a₃+ +a_q = p^3 q^3 ; p q . Then a₆ a₂₁ is equal to:

Options

  1. A41 11
  2. B31 121
  3. C11 41
  4. D121 1861

Correct answer

B. 31 121

Step-by-step solution

aligned & a₁+a₂+a₃+ +a_p a₁+a₂+a₃+ +a_q = p^3 q^3 & a₁+a₂ a₁ = 8 1 a₁+ (a₁+d )=8 a₁ & d=6 a₁ & Now a₆ a₂₁ = a₁+5 d a₁+20 d = & a₁+5 6 a₁ a₁+20 6 a₁ = 1+30 1+120 = 31 121 aligned

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