Question 309447: a card is drawn from a deck of cards numbered one through twenty. The card is NOT replaced and another card is drawn. Find the probability that a prime number is drawn and then a composite number.
Answer by Fombitz(32388)   (Show Source):
You can put this solution on YOUR website! Prime numbers from 1 to 20 are
2, 3, 5, 7, 11, 13, 17, 19
The number 1 is neither prime nor composite (if your teacher doesn't feel that way then modify as necessary).
That makes 8 numbers prime.
11 numbers composite.
1 special number (the number 1).
20 total.
P(prime)=8/20=2/5
Without replacement the total number of cards drops to 19.
P(composite)=11/19
P(prime, composite)=(2/5)(11/19)=22/95
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