Math help please!!!!!!!10pts best answer!!!!!?

Question

A game cost $1 to play. If you roll a sum of 7 on two dice you will win $10 or if you roll a sum of 11 you will win $ 5. All other sums will result in your losing your $ 1. What is the expected value?

Im lost..what do I do first?? Please help if you can...(thanks in advance)

Answer 1

Your expected value is how much you expect to win, total.

The chance of rolling a 7 is 6/36 (i.e. 6 combinations add up to 7).

The chance of rolling an 11 is 2/36 (both 6-5 and 5-6 give 11)

So the expectation is:

Exp = 10*(6/36) + 5*(2/36) - 1. (the -1 is the $ you paid)

Exp = 60/36 +10/36 -36/36 = 34/36.

So Exp is about 64 cents.