Let a_1,a_2,a_3,…. be a GP of increasing positive numbers. If the product of fourth and sixth terms is 9 and the sum of fifth and seventh terms is 24…
JEE Main 2023 — Mathematics Algebra
2023integereasy
Let a1,a2,a3,…. be a GP of increasing positive numbers. If the product of fourth and sixth terms is 9 and the sum of fifth and seventh terms is 24 , then a1a9+a2a4a9+a5+a7 is equal to
Official previous-year question
Held on 29 Jan 2023 · Verified 6 Jul 2026.
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Solution
Given,
a1,a2,a3,…. be a GP of increasing positive numbers,
And the product of fourth and sixth terms is 9
So, a4⋅a6=9⇒(a5)2=9⇒a5=3
Also given the sum of fifth and seventh terms is 24,