probability

Sara has a box of candies. In the box there are 8 pink candies, 7 purple candies and 5 blue candies. She takes one candy and records its color. She then puts it back in the box and draws another candy. What is the probability of taking out a pink candy followed by a blue candy? Calculate the...

There are 100 people in a sport centre. 67 people use the gym. 62 people use the swimming pool. 56 people use the track. 38 people use the gym and the pool. 31 people use the pool and the track. 33 people use the gym and the track. 16 people use all three facilities. A person is selected...

There are 10 true or false questions on a test. You do not know the answer to 4 of the questions, so you guess. What is the probability that you will get all 4 answers right? Probability you guess right is 1/2 or 0.5. Since each event is independent of the other events, we multiply 1/2 4...

a cookie jar contains 3 vanilla, 2 chocolate chip, and 7 gingersnap cookies. Of one cookie is taken at random from the jar, what is the probability that it will be a vanilla cookie? Total cookies = 3 + 2 + 7 Total cookies = 12 P(Vanilla) = Vanilla Cookies / Total Cookies P(Vanilla) = 3/12...

A gym has 18 exercise stations, including 2 rowing machines. What is the probability that a randomly selected exercise station will be a rowing machine? The probability is 2/18. We can simplify this fraction. Divide top and bottom by 2: 1/9

If A and B are independent events with P(A) = 0.2 and P(B) = 0.6, then P(A U B)=? We know the following formula for the probability of 2 events: P(A U B) = P(A) + P(B) - P(A intersection B) We're told A and B are independent, which makes P(A intersection B) = 0. So we're left with: P(A U B) =...

A laundry basket contains 30 socks, of which 9 are black. What is the probability that a randomly selected sock will be black? P(Black) = 9/30 Simplifying, we can divide top and bottom by 3: 3/10 3/10 as a percentage is 30%

There are 15 cards, numbered 1 through 15. If you pick a card, what is the probability that you choose an odd number or a two? We want the P(odd) or P(2). P(odd) = 1, 3, 5, 7, 9, 11, 13, 15 = 8/15 P(2) = 1/15 Add them both: 8/15 + 1/15 = 9/15 Simplified, we get 3/5.

If there are 52 cards in a pack, what is the probability of picking 2 kings in a row when the first card picked is not put back? 4 kings in a deck, and 52 cards in a pack. First draw, the probability of drawing a king is 4/52. Second draw, we have 51 cards left since we do not put the first...

For the normal distribution with parameters μ = 4, σ = 3 ; calculate P(x > 1) Using our calculator, we get P(x > 1) = 0.841345

μ = 5, σ = 4 ; calculate P(0 < x < 8) This is the same as P(x < 8) - P(x < 0). P(x < 8) using our calculator is 0.773373 P(x < 0) using our calculator is 0.10565 So we have 0.773373 - 0.10565 = 0.667723

There is a bag filled with 5 blue, 6 red and 2 green marbles. A marble is taken at random from the bag, the colour is noted and then it is replaced. Another marble is taken at random. What is the probability of getting exactly 1 blue? Find the total number of marbles in the bag: Total marbles =...

If 4 people have the same 7 shirts, what is the chance that they will wear the same shirt on one day? For each person, the probability they all wear the first shirt is 1/4 * 1/4 * 1/4 * 1/4 = 1/256 For each person, the probability they all wear the second shirt is 1/4 * 1/4 * 1/4 * 1/4 = 1/256...

A box contains 10 bells. There are 6 red bells and the rest are silver. What is the probability of picking two bells of the same color if the bell is replaced after each pick? If there are 6 red bells, then we have 10 - 6 = 4 silver bells. The problem asks for the probability of picking two...

A bag contains 666 red balls, 444 green balls, and 333 blue balls. If we choose a ball, then another ball without putting the first one back in the bag, what is the probability that the first ball will be green and the second will be red? Calculate total number of balls to start: Total Balls =...

A box is filled with 10 green cards, 4 blue cards, and 4 brown cards. A card is chosen at random from the box. What is the probability that it is a green or a brown card? Calculate Total Cards: 10 green cards + 4 blue cards + 4 brown cards = 18 cards "Or", means either or, so we want P(Green)...

A blue dice and a red dice are tossed what is the probability that a 6 will appear on both dice Each event is independent. P(Blue dice 6) = 1/6 P(Red Dice 6) = 1/6 P(Blue 6, Red 6) = 1/6 * 1/6 = 1/36

You are using a spinner with the numbers 1-10 on it. Find the probability that the pointer will stop on an odd number or a number less than 4. We want P(odd number) or P(n<4). Odd numbers are {1, 3, 5, 7, 9} n < 4 is {1, 2, 3} We want the union of these 2 sets: {1, 2, 3, 5, 7, 9} We have 6...

A box contains 5 plain pencils and 7 pens. A second box contains 4 color pencils and 4 crayons. One item from each box is chosen at random. What is the probability that a plain pencil from the first box and a color pencil from the second box are selected? Probability of plain pencil from first...

A class is made up of 6 boys and 12 girls. Half of the girls wear glasses. A student is selected at random from the class. What is the probability that the student is a girl with glasses? 1/2 of 6 is 3. So we want the probability we pick any of the 3 girls wearing glasses. We have a total of 6...