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Paragraph: Let a , x , y , z , b be in AP , where x + y + z =15 . Let a , p , q , r , b be in HP , where p ⁻¹+ q ⁻¹+ r ⁻¹= 5 3 Question: What is the value of a b ?

Options

  1. A10
  2. B9
  3. C8
  4. D6

Correct answer

B. 9

Step-by-step solution

S _ n = n 2 (a+l) a + x + y + z + b = 5 2 (a+b) a + b +15= 5 2 (a+b) a+b=10 ...(1) aligned & & 1 a + 1 p + 1 q + 1 r + 1 b = 5 2 ( 1 a + 1 b ) & 1 a + 1 b + 5 3 = 5 2 ( 1 a + 1 b ) aligned 3(a+b) a b = 10 3 . ...(2) aligned & 3 10 a b = 10 3 . & ab =9 aligned

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