Question

A bag contains two coins, one for which the probability of heads is equal to 1 and one for which the probability of heads is equal to p. A coin is selected at random, and three independent tosses of this coin result in three heads. What is the probability that a further independent toss of this coin will produce a head?a. p4/1 + p3.b. p3 - p2/1 + p3.c. p3/1 - p.d. 1/1 + p3.e. 1 + p4/1 + p3.

Answer 1

Answer: Option E is the correct answer; (1 + p⁴) / (1 + p³)

Step-by-step explanation:

P (3 head) = P(first and 3 heads) + P(second coin and 3 heads)

= (1/2)×1³ + (1/2)× p³ = (1/2) × (1 + p³)

therefore P(first coin given 3 heads) = (1/2)×1³/ ((1/2)×(1 + p³))

= 1 / (1 + p³)

Also P( second coin given 3 heads) = p³ /(1 + p³)

therefore P(4th toss in heads given first 3 are heads)  will be;

= P(first and 4th toss heads) + P(second and 4th toss heads)

=(1/( 1 + p³ )) × 1 + p³ / (1+p³) × p

= (1 + p⁴) / (1 + p³)

Therefore Option E is the correct answer