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

The correct answer is D. 9 \(\frac{9}{16}\)

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    âˆ´  p + q  =  9 + 9 16  =  9 9 16
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