Question

Suppose someone gives you 6 to 1 odds that you cannot roll two even numbers with the roll of two fair dice. This means you win 6 dollars if you succeed and lose 1 dollar if you fail. What is the expected value of this game to you. What can you expect if you play 200 times

Answer 1

0.75 ;

150

Explanation:

Probability of rolling two even numbers :

{1, 2, 3, 4, 5, 6}

P(even) = 3 / 6 = 1/2

From a roll of 2 dice :

P(even) * P(even) = 1/2 * 1/2 = 1/4 = 0.25

P(not even) = 1 - 1/4 = 3/4

X : ____ 6 _______ - 1

P(x) ____ 0.25 ____ 0.75

Expected value :

Σx*p(x) = (6*0.25) + (-1 * 0.75)

= 1.50 - 0.75

= 0.75

If 200 games are played :, n = 200

Expected value * n

0.75 * 200

= 150