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a, b, c are the first three terms of geo...

a, b, c are the first three terms of geometric series. If the H.M. of a and b is 12 and that of b and c is 36 then which of the following hold(s) good?

A

`n(n+1)`

B

`n^(2)`

C

`n(4-n)`

D

`n(6-n)`

Text Solution

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The correct Answer is:
A
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