Question

the sum of a GP with common ratio 3 is 364 and last term is 243 then the number of terms is​

Answer 1

Answer:

ans is 6

Step-by-step explanation:

Given r = 3

Last term, arn-1 = 243

a(3n-1) = 243

a×3n = 729…(i)

Sum of terms Sn, a(rn-1)/(r-1) = 364

a(3n-1)/(3-1) = 364

a(3n-1) = 364×2

a3n – a = 728

729 – a = 728

a = 1

Substitute a in arn-1 = 243

1(3n-1) = 35

n-1 = 5

n = 6

Hence 6 is the answer.

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