JEE Main 2023 · MathsNumerical answerNumerical valueMediumMulti-step

JEE Main 12 April 2023, Shift 1, Maths Q30

Question 30 of 90 in this shift, Maths question 30 of 30, Section B.

A fair

n

(n>1)

faces die is rolled repeatedly until a number less than

n

appears. If the mean of the number of tosses required is

\frac{n}{9}

, then

n

is equal to _______.

Official answer

NTA final key.

Chapter: Probability
Topic: Conditional Probability
Idea tested: Conditional Probability in Infinite Games

Same idea in other shifts

Asked 3× in all

29 Jan 2024, Shift 1 · Q19A fair die is thrown until 2 appears. Then the probability, that 2 appears in even number of throws, isMediumSingle correct
11 Apr 2023, Shift 2 · Q30Let the probability of getting head for a biased coin be $\frac{1}{4}$ . It is tossed repeatedly until a head appears. Let $N$ be the…HardNumerical value

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.