Probability

Question 1

What is probability?

Answer 1

probability of an event = (number of favourable outcomes) / (number of possible outcomes)

Question 2

What is the probability of drawing a red card from a standard deck?

Answer 2

probability = 26/52 = 0.5 or 50%

Question 3

What is the probability of drawing a face card from a standard deck? (note: assume the ace is not a face card)

Answer 3

probability = 12/52 = 0.23

Question 4

What is the probability of drawing a red card or a face card from a standard deck? (note: assume the ace is not a face card)

Answer 4

probability = (26 red + 6 face cards that are black)/52 = 0.62

Question 5

What is the probability of drawing a card that is not a face card from a standard deck? (note: assume the ace is not a face card)

Answer 5

12 face cards so 52-12 = 40 cards without a face

probability = 40/52 = 0.77

Question 6

What is the probability of drawing a card that is lower than 5? (note: do not count the ace as a 1)

Answer 6

2, 3 and 4 are lower than 5 x 4 suits = 12 cards

probability = 12/52 = 0.23

Question 7

What is the probability of drawing a 10 from a standard deck of cards?

Answer 7

probability = 4/52 = 0.08

Question 8

If there are 10 marbles in a bag, two of which are yellow, five of which are pink, one of which is orange and two of which are blue, what is the probability of drawing a yellow marble?

Answer 8

probability = 2/10 = 0.2

Question 9

If there are 10 marbles in a bag, two of which are yellow, five of which are pink, one of which is orange and two of which are blue, what is the probability of drawing a pink marble?

Answer 9

probability = 5/10 = 0.5

Question 10

If there are 10 marbles in a bag, two of which are yellow, five of which are pink, one of which is orange and two of which are blue, what is the probability of drawing a pink marble or a blue marble?

Answer 10

probability = (5 + 2) / 10 = 0.7