Question

joe is playing a game with a regular die. if the number that turns up is even he will gain 5 times the number that comes up. if it is odd, he will lose 10 times the number that comes up. he tosses a 3. express the results as an integer

Answer 1

find the expected value of each case 

1 comes up ---> 1/6 (-10) = -10/6 
3 comes up ---> 1/6 (-30) = -30/6 
5 comes up ---> 1/6 (-50) = -50/6 

2 comes up ---> 1/6 (10) = 10/6 
4 comes up ---> 1/6 (20) = 20/6 
6 comes up ---> 1/6 (30) = 30/6 

sum = 1/6 (-10 -30 -50 +10 +20 +30) = -30/6 = -5