Probability Rules
What is the probability of rolling a dice and it not landing on a 2?
⅚
50 people were asked about their preferred pizza toppings. Out of pepperoni and cheese, 9 liked both, 16 liked just pepperoni, how many liked cheese?
34
You roll a 6 sided dice 3 times. What is the probability that you roll a 5 every time.
0.0046
Todd rolls a dice 9 times, what is the probability that he rolls a 3 after his third roll.
0.856
If 2 coins are flipped what is the probability that both will land on tails?
0.25
If you roll a dice what is the probability of it landing on a 6 or 3 or a 5?
3/6 or ½
70 people were asked if they like vanilla or chocolate ice cream. 55 said they like vanilla, 15 said they like chocolate, 35 said they prefer both. How many preferred only chocolate and how many preferred only vanilla?
15 chocolate, 35 both, 20 vanilla
The hospital is running a test to see how much of the population of Watertown has bad eyesight. They ask 10,000 people whether they wear glasses or contacts. The group had shown to have a 85% chance of having bad eyesight. What is the probability that the 10th person asked was the first to have good eyesight?
0.0374
Five people are going to get tested for the coronavirus. It has been proven that 70% of the people who get tested, are tested positive. What is the chance of 3 of them having coronavirus?
0.3087
If a dice is rolled 4 times what is the probability that it is even every time?
0.0625
Beth wants to make an experiment. She wants to test to see whether people in her class use mechanical pencils or wooden pencils more. There are 15 people in her class. She calculated that the probability of people using mechanical pencils is ⅗ and that the probability that people use wooden pencils is 6/9 . Did she calculate the probability correctly? If not, explain what she did wrong.
⅗ of 15 is also 9/15 which means that 9 people use mechanical pencils. If she is correct then 6/9 of 15 should be equal to 6 people (6/15). However 6/9 isn’t equal to 6/15.
400 people were surveyed and asked if they prefer going out with friends, staying home, or going out alone, everyone answered.
245 preferred going out with friends, 170 preferred staying home, 155 preferred going out alone. 80 prefer staying home and going out with friends. 75 prefer staying home and going out alone. 85 prefer going out alone and going out with friends. 70 people prefer all. How many people preferred going out with friends? how many preferred going out alone? How many preferred to go out alone?
150 friends, 85 home, 65 alone, 5 home/alone, 15 friends/alone, 10 home/friends, 70 all.
If there are 5 black marbles and 4 red marbles what is the probability that you get all 4 red ones in 4 tries?
0.0079
There are 6 colored pieces of paper in a hat. 2 are green, 3 are yellow, and 1 is red. What is the probability you pull a yellow on your first try?
.0833
The probability of flipping a water bottle is around 30%. If you flip a water bottle 5 times, what is the probability that you land it at least twice?
.00369