Question

Two tokens are such that one is colored

redon both sides while the other is red on one side and blue on
theother side. One of the tokens is picked at random and
flipped,landing red side up. What is the probablitiy that the other
side isalso red?

Answer 1

The probablitiy that the other side is also red is 0.67 (2/3)

Explanation:

The conditional probability of A given B is denoted as P(A|B) and has the equation:

P(A|B)= (P(A) × P(B|A)) / P(B)

the probability that getting red after picking one token and flipping, P(R),

=probability of picking two side red token and getting red +

the probability of picking one side red one side blue token and getting red

=0.5 × 1 + 0.5 × 0.5 = 0.75

P(TR|R) means the probability of picking two side red token given that token landed red and equals to:

P(TR|R) = P(TR) × P(R|TR) / P(R) = 0.5 × 1 / 0.75 =2/3 ≈ 0.67