# Probability - high school - examples

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 impossible event and 1 (100%) means the certainty event.

1. Today in school
There are 9 girls and 11 boys in the class today. What is the probability that Suzan will go to the board today?
2. One three
We throw two dice. What is the probability that max one three falls?
3. Lathe
95% of the components manufactured on the lathe comply with the standard, of which 80% of the components are first-class. How likely can we expect a manufactured part to be first class?
4. Probability of intersection
Three students have a probability of 0.7,0.5 and 0.4 to graduated from university respectively. What is the probability that at least one of them will be graduated?
5. Rectangle
In rectangle with sides, 10 and 8 mark the diagonal. What is the probability that a randomly selected point within the rectangle is closer to the diagonal than to any side of the rectangle?
6. Ace
From complete sets of playing cards (32 cards) we pulled out one card. What is the probability of pulling the ace?
7. Word
What is the probability that a random word composed of chars T, H, A, M will be the MATH?
8. Two doctors
Doctor A will determine the correct diagnosis with a probability 86% and doctor B with a probability 86%. Calculate probability of correct diagnosis if patient is diagnosed by both doctors.
9. Dice
How many times must throw the dice, the probability of throwing at least one six was greater than 90%?
10. Scrap
From 6 products are 3 scrap. What is the probability that the random pick of 2 products have no defective product?
11. Sales
From statistics of sales goods, item A buy 51% of people and item B buys 59% of people. What is the probability that from 10 people buy 2 item A and 8 item B?
12. Dices
We will throw two dice. What is the probability that the ratio between numbers on first and second dice will be 1:2?
13. Event probability
The probability of event P in 8 independent experiments is 0.33. What is the probability that the event P occurs in one experiment (probability is same)?
14. Balls
From the urn in which are 7 white balls and 17 red, gradually drag 3-times without replacement. What is the probability that pulls balls are in order: red red red?
15. Events
Event N has probability of 0.24. What is the probability that the event N occurs in 8, 5, 4 try.
16. Pizza
A school survey found that 12 out of 15 students like pizza. If 6 students are chosen at random, what is the probability that all 6 students like pizza?
17. Hockey players
After we cycle five hockey players sit down. What is the probability that the two best scorers of this crew will sit next to each other?
18. Lottery
The lottery is 60000 elk in which 6200 wins. What is the probability that the purchase of 12 elks won nothing?
19. Monty Hall
Suppose you're on a game show, and you're given the choice of three doors: Behind one door is a car; behind the others, goats. You pick a door, say No. 1, and the host, who knows what's behind the doors, opens another door, say No. 3, which has a goat. W
20. Family
What is the probability that a family with 7 childrens have: exactly 5 girls? 7 girls and 0 boys? Consider the birth probability of a girl is 48.69% and boy 51.31%.

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