Question

find the 12th term of a G.P whose 8th term is 192 and the comman ratio is 2.

Answer 1

nth term of a GP is given as:
\[t_n=ar^{n-1}\]
we are given:
\[t_8=192 \] and r=2

Answer 2

@poojav: If you know the 8th term of a G.P. and you know the common ratio, then you can arrive at the 9th term, 10th term, etc. by multiplying the previous term by the common ratio.
So 9th term = 192 x 2 = 384; 10th term = 384 x 2 = 768; 11th term = 768 x 2 = 1536 and 12th term = 3072.
Here the 8th term and 12th term were closeby and so I used this method. If they are far apart you will have to solve the equations for 'a' and 'r'.