In the SuperLottery, three b***s are drawn (at random) from ten white b**ls numbered from $1$ to $10$, and one SuperB*ll is drawn (at random) from ten red b***s numbered from $11$ to $20$. When you buy a ticket, you choose three numbers from $1$ to $10,$ and one number from $11$ to $20$. If the numbers on your ticket match at least two of the white b***s or match the red SuperB*ll, then you win a super prize. What is the probability that you win a super prize?

blobfishesarecool Oct 17, 2020

#1**0 **

Case 1: Superball

The probability is 1/10, because you choose 1 out of 10.

Case 2: 2 whites

The probability is 1/C(10,2) = 1/45, because you choose 2 out of 10.

Case 3: 3 whites

The probability is 1/C(10,3) = 1/120, because you choose 3 out of 10.

Adding these, you get 1/10 + 1/45 + 1/120 = 47/360.

Guest Oct 31, 2020