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In an increasing gp the sum of the first and the last term is 66. The product of the second and the last but one is 128 and the sum of the sum of the terms is 126 ..then the no. Of terms in the series is........

In an increasing gp the sum of the first and the last term is 66. The product of the second and the last but one is 128 and the sum of the sum of the terms is 126 ..then the no. Of terms in the series is........

Grade:12

4 Answers

Nicho priyatham
625 Points
7 years ago
6
plz approve if useful
Nicho priyatham
625 Points
7 years ago
a+arn-1=66
ar*arn-2=128
a(rn-1)/(r-1)=63
solving 1 and 2 we get 
rn-1=32
so rn=32r put it in equation 3
to get r=2
 
Manoj Patra
22 Points
7 years ago
Thanks
Kushagra Mishra
34 Points
6 years ago
6

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