Question

for a GP a=3 r=2 Sn=765 . find n​

Answer 1

Answer:

Hope it helps u..........

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Answer 2

Answer:

Sn=a(r^n -1)/r-1

=3(2^n-1)/1

765\3=2^n -1

255+1=2^n

256. =2^n

2^8=2^n

n=8