# Probability - practice problems

Probability is the measure of the likeliness that an event will occur. The probability (chance) is a value from the interval <0;1> or in percentage (0% to 100%) expressing the occurrence of some event. 0 is an impossible event, and 1 (100%) means the certainty event.#### Number of problems found: 461

- A band

A band played an encore at 2 of its last 4 shows. Considering this data, how many of the band's next 14 shows would you expect to have an encore? - Drunken drivers

40% of drivers driving between 11 pm and 5 am are drunken drivers. In a random sample of 20 drivers driving between 11 pm and 5 am, find the probability that: A) Exactly 12 will be drunken drivers B) At least 7 will be drunken drivers C) At most 5 will be - A bag 6

A bag contains 3 red marbles, 8 blue marbles, and 5 green marbles. If two marbles are drawn out of the bag, what is the probability, to the nearest 1000th, that both marbles drawn will be blue? - The usage

The battery usage time installed in a particular smartphone has a Normal distribution with a mean of 25.2 hours and a standard deviation of 7.5 hours. What is the probability of usage time greater than 32? - TF quiz

Gomer has to take a 5 question true/false quiz, but he hasn't studied. He will guess at each problem. In how many different ways is it possible to answer the quiz questions? How likely is it that he will get a score of 100%? - Defect rate

A manufacturing machine has a 3% defect rate. If 9 items are chosen randomly, what is the probability that at least one will have a defect? - Library and gym

In a town, 7/8 of the population has a library card, and 3/4 has a gym membership. What fraction of the population has either a library card or a gym membership? - A coin

Suppose you tossed a coin 12 times. The coin landed on heads 9 times and on tail 3 times. What is the probability of landing on tails? - And or logic

If A and B are events with P(A)=0.3, P(A OR B)=0.76, and P(A AND B)=0.04, find P(B). Enter your answer in decimal form, rounded to one place. - A basket 4

A basket contains 9 fruits, where 4 are oranges, and the rest are mangoes. Three fruits are taken out one at a time and put aside. Find the probability that 3 are oranges. - Three coins

In a game of chance where three coins are tossed, a player wins if two heads and a tail come up. What are the chances of this occurring? - And - or probability rules

Given P(A)=0.4, P(B)=0.56, and P(A and B)=0.274, find the value of P(A or B), rounding, if necessary. - Ekene and Amina

The probability that Ekene will be alive in 5 years' time is 3/4, and the probability that his wife Amina will be alive in 5 years' time is 2/5. Find the probability that in 5 years' time: a) both of them will be alive b) only Ekene will be alive - Two dice 3

Two dice are thrown together. What is the probability that the number obtained on one of the dice is a multiple of the number obtained on the other dice? 2/3 9/36 12/36 11/18 - A single

A single, standard number cube is tossed. What is the probability of getting a number greater than 3? - Q10 - investigate

A nutritionist who investigates fruits reported that the average weight of a raspberry is 4.4 g with a standard deviation of 1.28 g. What is the probability that a randomly selected raspberry would weigh less than 3.1 grams? Let X represent the weight of - A total 3

A total of 160 families with 4 children each were surveyed with the following results. Boys; 4; 3; 2; 1; 0 Girls ; 0; 1; 2; 3; 4 Families; 7; 50; 55; 32; 16 Let the probability of picking a boy or a girl be 1/2. Let P=boy, Q=girl. What is the probability - Pet store 2

A pet store is having a prize giveaway. The spinner shows the type of toy a customer can win for their pet. If a customer spins the spinner and it lands on a cat, they will win a free cat toy. If the spinner is spun 540 times throughout the day, about how - Bulb life

Tests show that the lives of light bulbs are normally distributed with a mean of 750 hours and a standard deviation of 75 hours. Find the probability that a randomly selected light bulb will last between 675 and 900 hours. - Five roommates

Five roommates will move into a house with four bedrooms: one double room and three single rooms. The five roommates propose that they draw names to determine the order in which they pick the bedrooms, assuming that the first three names drawn will choose

Do you have homework that you need help solving? Ask a question, and we will try to solve it.