Calculating Probability
A bag contains 3 red marbles and 7 blue marbles. What is the probability of picking a red marble?
30%
You flip a coin twice. What is the probability that both flips result in heads?
25%
In a survey, 40% of all pet owners own a dog, 30% own a cat, and 50% do not own either pet. What percentage of pet owners own a cat and a dog?
20%
If you draw a card from a deck, what is the probability it’s a heart, given it is a red card?
50%
If you roll a six-sided die, what is the probability of rolling an even number?
1/2
A family has 3 children. What is the probability that they have exactly 2 boys?
3/8
In a survey, 40% of all pet owners own a dog, 30% own a cat, and 50% do not own either pet. What percentage of pet owners own just a cat
10%
A bag contains 5 green marbles, 4 red marbles, and 6 blue marbles. If a green marble is drawn and not replaced, what is the probability that the next marble drawn is red?
2/7
A spinner has four equal sections colored red, blue, green, and yellow. What is the probability of landing on either red or blue?
50%
Two cards are drawn from a deck without replacement. What is the probability that both cards are aces?
1/221 or 0.0045
In a neighborhood of 300 homes, 180 households own a car, 160 households own a bicycle, and 40 households own neither. What is the probability that a randomly selected household owns only a bicycle?
80/300 = 27%
If two cards are drawn from a deck without replacement, what is the probability that the second card is a spade, given that the first card was a spade?
4/17
A bag contains 4 yellow marbles, 5 red marbles, and 6 green marbles. If one marble is drawn at random, what is the probability it is not red?
2/3
In a bag of 10 jelly beans (5 red and 5 blue), if you pick two without replacement, what is the probability that at least one is blue?
7/9
In a classroom of 28 students, 15 play soccer, 12 play basketball, and 8 play both sports. What is the probability that a randomly selected student doesn't play either sport?
9/28 = 32%
Two athletes have probabilities of 0.7 and 0.8 of hitting a target. What is the probability that exactly one athlete hits the target?
38%
A card is drawn from a standard deck of 52 cards. What is the probability of drawing a face card or a heart?
22/52 = 11/26
Two dice are rolled. What is the probability that the sum is at least 9 or that both dice show the same number?
7/18
A card is drawn from a standard deck of 52 cards. What is the probability that you draw either a Jack or a black card?
7/13 = 53.8%
A jar contains 10 red balls and 8 green balls. Two balls are drawn without replacement. What is the probability that both balls are green, given the second ball is green?
7/17