probability

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...

if you have a bag with 7 red balls in it and 3 yellow balls in it, whats the probability of pulling out a yellow ball P(Yellow) = 3/(3 + 7) P(Yellow) = 3/10 or 0.3.

An ordinary fair die is rolled twice. The face value of the rolls is added together. Compute the probability of the following events: Event A: The sum is greater than 6. Event B: The sum is divisible by 5 or 6 or both. Sum greater than 6 = 7/12 Sum is divisible by 5 or 6 or both This means a...

There are 5 red and 4 black balls in a box. If you pick out 2 balls without replacement, what is the probability of getiing at least one red ball? First list out our sample space. At least one means 1 or 2 red balls, so we have 3 possible draws: Red, Black Black, Red Red, Red List out the...

You roll two six-sided dice. What is the probability that the sum is less than 13? The probability is 1, or 100%, since the maximum sum of two six-sided dice is 12.

What is the probability of drawing an ace from a deck of 52 cards? With 4 Aces in the deck, the probability we draw an Ace is: 4/52 Simplifying this fraction, we get 1/13

There is a stack of 10 cards, each given a different number from 1 to 10. Suppose we select a card randomly from the stack, replace it, and then randomly select another card. What is the probability that the first card is an odd number and the second card is greater than 7. First Event: P(1, 3...

A parking lot has sixty-eight parking spaces numbered from 1 to 68. There are no cars in the parking lot when Jillian pulls in and randomly parks. What is the probability that the number on the parking space where she parks is greater than or equal to 21? We want P(X>=21). This is also found by...

At a certain university, 60% of the students enrolled in a math course, 50% are enrolled in an English course, and 40% are enrolled in both. What percentage of the students are enrolled in an English course and/or a math course? Let M be a math course, E be an english course, We are given...

A pair of dice is cast. what is the probablitly that the sum is less than 5? Using our two dice calculator, we get 1/6 or 16.67%

Which of the following is the probability that a green marble will be selected from a bag containing 9 red marbles 6 blue marbles 7 green marbles and 11 yellow marbles if one is selected randomly? Total marbles in the bag: 9 red + 6 blue + 7 green + 11 yellow = 33 P(Green) = Green Marbles /...

A coin is tossed and a die is rolled. Find the probability pf getting a head and a number greater than 4. Since each event is independent, we multiply the probabilities of each event. P(H) = 0.5 or 1/2 P(Dice > 4) = P(5) + P(6) = 1/6 + 1/6 = 2/6 = 1/3 P(H) AND P(Dice > 4) = 1/2 * 1/3 = 1/6

52 card deck what is the probability of being dealt a two? There are four 2's in a deck, so we have 4/52. 4/52 is reducible to 1/13

What is the probability that a month chosen at random has less than 31 days? Months with 31 days: January March May July August October December 7 months out of 12 have 31 days, so our probability is 7/12

A bag contains 3 white balls and 2 black balls. Another bag contains 2 white and 4 black balls. A bag and a ball are picked random. Then probability of that the ball will be white is: Probability that you pick any bag is 0.5. Bag 1 White Ball = 0.5(3/5) = 3/10 = 0.3 Bag 2 White Ball = 0.5(2/6)...

The weight of a 9.5-inch by 6-inch paperback book published by Leaden Publications, Inc., is 16.2 oz. The standard deviation is 2.9 oz. What is the probability that the average weight of a sample of 33 such books is less than 15.89 oz? Using our z-score calculator, we get: 0.271

if n(A) = 6, n(A intersect B) = 2 and n(A union B) = 11, find n(B). n(A union B) = n(A) + n(B) - n(A intersect B) Plugging in our given values, we have: 11 = 6 + n(B) - 2 11 = 4 + n(B) Subtract 4 from each side: n(B) = 7

A blue die and a green die are rolled. Find the probability that the blue and green are both less than 6 P(Blue not 6) = 5/6 P(Green not 6) = 5/6 Each one is independent of the other, so the probability that both are less than 6 is: P(Both not 6) = P(Blue not 6) x P(Green not 6) P(Both not 6)...

A box contains 4 plain pencils and 4 pens. A second box contains 5 color pencils and 3 crayons. One item from each box is chosen at random. What is the probability that a pen from the first box and a crayon from the second box are selected? First box, P(pen) = 4/8 = 1/2 = 0.5 Second box...

The Oakdale High School Speech and Debate Club hosted its annual car wash fundraiser. Each club member brought a bottle of car wash soap, so there were 8 total bottles. 6 of the bottles contained orange soap. If a club member randomly selects 5 bottles to pour into the first soap bucket, what is...