Sequences Series : Geometric Progression

Question 3
The difference between the 3^rd and 5^th term of a GP is 48; the difference between 9^th and 5^th term of the same GP is 4320. The common difference of the GP

1. Is equal to 3
2. Can be one of two values
3. Is equal to -3
4. Cannot say with given data

Correct Answer is Can be one of two values. Choice (2)

Explanatory Answer

ax² - ax⁴ = 48         ....... eqn (1)

ax⁴ - ax⁸ = 4320         ....... eqn (2)

Dividing equation 2 by equation 1

x²(x²+1) = 90, or x = +3 or -3.

Choice (2)

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AIEEE Math Problems, Practice Questions and Answers : Listed Topicwise

Sets, Relations & Functions		Permutation Combination		Sequences & Series
Limits, Continuity & Differentiability		Statistics & Probability		Trigonometry
Mathematical Reasoning