Question #2af10

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Answer 1 · 2017-05-23T12:23:23

Common ratio is $1 1/2$

$3$ rd term of A.P is $a+(3-1)b = a+2b$

$5$ th term of A.P is $a+(5-1)b = a+4b$

$8$ th term of A.P is $a+(8-1)b = a+7b$

$3$ consecutive terms of G.P are $a+2b,a+4b,a+7b$ .
in G.P
$(a+4b)/(a+2b)=(a+7b)/(a+4b) or (a+4b)^2=(a+2b)(a+7b)$ or

$cancela^2+8ab+16b^2= cancela^2+9ab+14b^2$ or
$2b^2= ab or a= 2b$

$3$ consecutive terms of G.P are $4b,6b,9b$

Common ratio is $r= (6b)/(4b)=3/2 or (9b)/(6b)= 3/2$ [Ans]