Progression Practice Test 1

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Question : 15 of 23

Marks: +1, -0

Find the sum of the six terms of the sequence

8,-2,1/2,-1/8.....

$819/127$
$820/128$
$821/128$
$819/128$
$820/127$

Solution:

The given sequence is a GP with a = 8 and

r=-1/4

We know that

S_6={a(1-(-1/4))}/{1-(-1/4)}

={8(1-1/4^6)}/{5/4}

=819/128

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