Multiple choice

The second term of a G.P is 24 and the fifth term is 81. Find the series

  1. 16, 36, 24, 54,,,,,,,,

  2. 24, 36, 53 ....

  3. 16, 24 36, 54 ....

  4. None of these
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C Correct answer
Explanation

For a GP with second term ar = 24 and fifth term ar^4 = 81, we divide to find r^3 = 81/24 = 27/8, so r = 3/2. Then a = 24/r = 24/(3/2) = 16. The series is 16, 16×(3/2), 16×(3/2)^2, ... = 16, 24, 36, 54, 81,...

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