Homework this weekend
a. What is the probability of picking an “A” card and then an “10” card from a deck?
(Black Jack)
-there is a condition, A first, then 10. We multiply the probability
A – 10
4 Aces/52 cards, 4/51 (51 cards left after one card is taken out)
4/52 x 4/51 = (4x4)/(52x51) = 16/2652 or 0.006 or 0.6%
b. What is the probability of picking three “7” cards in a row from a deck?
7-7-7 (after a card is taken out, it will not be put back to the deck)
4/52 (four “7” cards in a deck), 3/51, 2/50 (only two “7” are left, with 50 cards)
4/52 x 3/51 x 2/50 = (4x3x2)/(52x51x50) = 24/132600 = 0.0001 or 0.01% (almost impossible)
4/52 to get one “7” card
c. What is the probability of picking two red cards in a row from a deck?
26/52 (26 red cards) x 25/51 (25 red left, in a deck of 51 cards)
26/52 x 25/51 = (26 x 25)/(52 x 51) = 650/2653 = 0.24 or 24%
Let’s practice
g) When a card is removed from a deck, it will not be put back
What is the probability of getting three black cards in a row?
First black card 26/52
Second black card 25/51 (25 black cards left)
Third black card 24/50 (24 black cards left)
26/52 x 25/51 x 24/50 = (26x25x24)/(52 x 51 x 50) = 15600/132600 = 11%
h) When a card is removed from a deck, it will not be put back
What is the probability of getting a King, a Queen and a Jack in a row
King 4/52
Queen 4/51
Jack 4/50
4/52 x 4/51 x 4/50 = (4x4x4)/(52x51x50) = 64/132600
i) When a card is removed from a deck, it will not be put back
What is the probability of getting 7-7-7-7?
4/52 x 3/51 x 2/50 x 1/49 = (4x3x2x1)/(52x51x50x49) = 24/6497400 (impossible
Real life examples:
How to win the Lotto 649?
There are 49 numbers. To win the first price, must pick those six numbers correctly
_____, ______, _____, ______,_____, ______,
1/49 1/48, 1/47 1/46 1/45 1/44
Chance of winning the 649 is
(1/49)x(1/48)x(1/47)x(1/46)x(1/45)x(1/44)
1/(49x48x47x46x45x44) = impossible, very small number
Figure the rules in Lotto Max, and determine the chance of winning the first price
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