Three cards are selected at random from a group of 7. Two of the cards have been marked with winning numbers. What is the probability that none of the 3 cards will have a winning number?
1 Answer
May 26, 2017
Explanation:
We are picking 3 cards from a pool of 7. We can use the combination formula to see the number of different ways we can do that:
Of those 35 ways, we want to pick the three cards that do not have any of the two winning cards. We can therefore take the 2 winning cards from the pool and see how many ways we can pick from them:
And so the probability of not picking a winning card is:
