A box contains 5 red and 5 blue balls. Two balls are withdrawn randomly. If they are the same color, then you win NT$11 dollars. However, if they are different colors, then you win –NT$ 10 dollars (that is, you lose NT$ 10 dollars). Calculate
(a) the expected value of the money you win.
(b) the variance of the money you win.
I will be Glad if you can help me !