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Question
Find the 12th term of a G.P. whose 8th term is 192 and the common ratio is 2.
Solution
Let the first term of the geometric progression = a
Common ratio = 2
12th term = a × 212−1 = 211 a
8th term = a × 28−1 = a × 27 = 128a
Given: 8th term = 192
∴ 128a = 192
or a = `192/128 = 3/2`
∴ 12th term = `1^11 xx 3/2`
= `2^10 xx 3`
= 1024 × 3
= 3072
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