Let a_1, a_2, …, a_10 be a GP. If a_3/a_1 = 25, then a_9/a_5 equals

Let a_1, a_2, …, a_10 be a GP. If a_3/a_1 = 25, then… — JEE Main 2019 Mathematics PYQ

JEE Main 2019 · 11 Jan · Shift I

Let

a_1, a_2, \ldots, a_{10}

be a GP. If

\dfrac{a_3}{a_1} = 25

, then

\dfrac{a_9}{a_5}

equals

Show answer and solution

Correct option: D

Solution

In a GP with common ratio r, a₃/a₁ = r² = 25, so r = 5.

Then a₉/a₅ = r⁴ = 5⁴.

[JEE Main 2019 · 11 Jan · Shift I]

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