Q2 of 97 Page 192

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

Given: 8th of the G.P. is 192 and common ratio is 2.


That is,


a8 = 192 and r = 2.


We know that in G.P an = arn-1


Here, n: number of terms


a: First term = 5/2


r: common ratio


∴ a8 = a(2)8-1 (∵ r = 2 and n = 8)


⇒ 192 = a(2)7


⇒ a × 128 = 192



Now,



∴ a12 = 3072


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