Sequence And Series Question 301
Question: If five G.M.?s are inserted between 486 and 2/3 then fourth G.M. will be
[RPET 1999]
Options:
A) 4
B) 6
C) 12
D) - 6
Show Answer
Answer:
Correct Answer: B
Solution:
Let $ G_1,G_2,G_3,G_4,G_5 $ be the G.M.?s are inserted between 486 and 2/3. So total terms are 7. $ T_{n}=a{r^{n-1}} $
Þ 2/3 = 486 $ {{(r)}^{6}} $
$ \Rightarrow r=1/3 $ Hence 4th G.M. will be, $ T_5=ar^{4}=486,{{(1/3)}^{4}}=6 $ .
BETA
