JEE Main 2023 · MathsMultiple choiceSingle correctMediumMulti-step

JEE Main 13 April 2023, Shift 1, Maths Q18

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

A coin is biased so that the head is 3 times as likely to occur as tail. This coin is tossed until a head or three tails occur. If X denotes the number of tosses of the coin, then the mean of X is

(1) $\frac{21}{16}$ Official answer
(2) $\frac{15}{16}$
(3) $\frac{81}{64}$
(4) $\frac{37}{16}$

Official answer

Option 1

NTA final key.

Chapter: Probability
Topic: No close match in our taxonomy
Idea tested: No close match in our taxonomy