1.

If the 2nd , 5th and 9thterms of anon-constant A.P. are in G.P., then thecommon ratio of this G.P. is :(1) `8/5`(2)`4/3`(3)1 (4) `7/4`A. `4/3`B. 1C. `7/4`D. `8/5`

Answer» Correct Answer - A
Given a+d,a+4d,a+8d are in G.P.
`therefore (a+4d)^(2)=(a+d)(a+8d)=a^(2)+9ad+8d^(2)`
`rArr8d^(2)=adrArra=8d`
`therefore9d,12d,16d` are G.P.
Common ratio `r=12/9=4/3`


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