Question

Peter randomly draws a card from a deck of 24. The odds in favor of his drawing a spade from the cards are 1:3. What is the probability ratio for Peter to draw a spade

Answer 1

1 /4

Explanation:

Given that :

Let :

P(S) = probability of drawing a spade

Odds in favor of drawing a spade = 1:3 ; this could be interpreted as :

P(drawing a spade)/P(not drawing a spade) = 1:3

P(S) / P(S') = 1/ 3

P(S') = 1 - P(S)

P(S) / (1 - P(S)) = 1 / 3

Cross multiply :

3P(S) = 1 - P(S)

Collect like terms

3P(S) + P(S) = 1

4P(S) = 1

P(S) = 1/4

Hence, probability ratio of drawing a spade P(S) = 1/4