If 36, p,\(\frac{9}{4}\) and q are consecutive terms of an exponential sequence (G.P), find the sum of p and q.

A.

9/16

B.

81/16

C.

9

D.

9 \(\frac{9}{16}\)

Correct answer is D

GP : 36, P, \(\frac{q}{4}\), q, ... p + q = ?

Recall, common ratio, r = Tn
Tn-1
= T2
T1
= T3
T2
= T4
T3


 

P
36
= 9
4
÷ p ;       p\(^2\) = 9
4
x 36 ;     p\(^2\) = 81  


 

p = 9         ∴      r = T2
T1
    =   9
36
    =  1
4


 

Also r  = T4
T3
   = q ÷ 9
4



∴ \(\frac{1}{4}\) = q ÷ \(\frac{9}{4}\) ;

\(\frac{9}{4}\) = 4q

16q = 9 ,   q = 9
16
   ∴  p + q  =  9 + 9
16
 =  9 9
16