JEE Main 2021 · MathsMultiple choiceSingle correctEasyCalculation

JEE Main 26 February 2021, Shift 1, Maths Q78

Question 78 of 90 in this shift, Maths question 18 of 30, Section A.

The sum of the infinite series

1+\frac{2}{3}+\frac{7}{3^2}+\frac{12}{3^3}+\frac{17}{3^4}+\frac{22}{3^5}+\ldots\ldots

is equal to :

(1) $\frac{9}{4}$
(2) $\frac{11}{4}$
(3) $\frac{13}{4}$ Official answer
(4) $\frac{15}{4}$

Official answer

Option 3

NTA final key.

Chapter: Sequences and Series
Topic: Arithmetico-Geometric Series
Idea tested: Sum of Infinite AGP

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Asked 5× in all

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Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.