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Let a, b, c be in A.P. then 1/ab, 1/ca and 1/bc are in

  1. AP
  2. HP
  3. GP
  4. none of these

Answer (Detailed Solution Below)

Option 1 : AP
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Detailed Solution

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Concept:

If a,b, c are in AP, then 2b = a + c or b - a = c - b

Calculation:

Given: a, b, c are in AP

Let 1/ab, 1/ca and 1/bc be in AP

⇒

⇒ b - c = a - b 

⇒2b = a + c

⇒ a,b, c are in AP, which is true.

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