Sequence And Series Question 267
If A.M. of two terms is 9 and H.M. is 36, then G.M. will be 12
[RPET 1995]
Options:
18
12
16
D) None of the above
Show Answer
Answer:
Correct Answer: A
Solution:
(A.M.) (H.M.)  $ =ab={{(G.M.)}^{2}} $
$ \Rightarrow  $  $ 9\ .\ 36={{(G.M)}^{2}} $
$ \Rightarrow  $  $ =\frac{n(n+1)(3n^{2}+7n+2)}{12} $ .
 BETA
  BETA 
             
             
           
           
           
          