Do you know the Expected Value formula?
They have already done the hard work for you.
Elena plays a game where she tosses two dice.
If the sum is 6, she wins 3 points. (The probability of the sum being 6 is 5/36)
If the sum is greater than 6, she wins 1 point (The probability of the sum being greater than 6 is 21/36).
If the sum is less than 6, she loses k points. (The probability of the sum being less than 6 is 10/36).
Find the value of k for which Elena's expected number of points is zero.
We have: .
. . . .