Question

You are given two coins, one unbiased and the other two-tailed (both sides are tails). Choose a coin at random and toss it once (assume that the probability of choosing the unbiased coin is 3 4 ). Given that the result is tails, find the probability that the two-tailed coin was chosen

Answer 1

Answer:6/7

Explanation:

so basically given observation is u got a tail from a biased coin.

so our favorable case is getting a tail from biased coin.

we will use the probability for it:

p1= probability of getting choosing biased coin and getting tail =probability of choosing biased coin* probability of tail = 3/4*1

p2= probability of choosing a fair coin and getting tail= probability of choosing fair coin*probability of getting tail on it = 1/4*1/2 = 1/8

so p(E)= p1/(p1+p2)= 3/4/(3/4+1/8)=7/8