Probabilities help?

Three cards are selected at random from a group of 7. Two of the cards have been marked with winning numbers.


a. what is the probability that exactly 1 of the 3 cards has a winning number?


b. what is the probability that at least 1 of the 3 cards has a winning number?


c.what is the probability that non of the 3 cards has a winning number?

Probabilities help?
a.


=(P of picking 1 win) x (P of picking 1 loss) x (P of picking another loss)


=2/7 x 5/6 x 4/5


=40/210


=0.1904


=19%





b.


=(100%) - (P of Picking no winning number)


=100% - 29% (see c)


=71%








c.


=(P of picking 1 loss) x (P of picking 2nd loss) x (P of picking 3rd loss)


=5/7 x 4/6 x 3/5


=60/210


=.2857


=29%





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Remember: Everytime you take a card you have one less card in the pack.