# Combinatorics - examples - page 2

1. Dice
How many times must throw the dice, the probability of throwing at least one six was greater than 90%?
2. Football league
In the 5th football league is 10 teams. How many ways can be filled first, second and third place?
3. Candy
How many ways can divide 16 identical candies to 4 children?
4. Playing cards
How many possible ways are to shuffle 7 playing cards?
5. Pairs
At the table sit 8 people, 4 on one side and 4 on the other side. Among them are 3 pairs. Every pair wants to sit opposite each other. How many ways can they sit?
6. Scrap
From 6 products are 3 scrap. What is the probability that the random pick of 2 products have no defective product?
7. 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?
8. Morse alphabet
Calculate how many words of Morse code to create compiling commas and dots in the words of one to four characters.
9. Stacks
Annie has a total of \$ 702. The money must be divided into stacks so that each buyer has the same amounth of dollars. How many options she have?
10. Coin and die
Flip a coin and then roll a six-sided die. How many possible combinations are there?
11. Lock
Combination lock will open when the right choice of 5 numbers (from 1 to 12 inclusive) is selected. A. How many different lock combinations are possible? B. Is he combination lock named appropriately?
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. N-gon
How many diagonals has convex 11-gon?
14. 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)?
15. Subsets
How many are all subsets of set ??
16. 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?
17. Shooter
The probability that a good shooter hits the center of the target circle I is 0.1. The probability that the target hit intercircle is II 0.58. What is the probability that it hits the target circle I or II?
18. Pairs
From the five girls and four boys teachers have to choose one pair of boy and girl. A) How many such pairs of (M + F)? B) How many pairs where only boys (M + M)? C) How many are all possible pairs?
19. Events
Event N has probability of 0.24. What is the probability that the event N occurs in 8, 5, 4 try.
20. 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?

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