Variations + reason - practice problems
Number of problems found: 131
- Five couples
In how many ways can 5 couples arrange themselves in a row if they stay together? - A ferry
A ferry with a capacity of 10 people takes a group of 13 men and 7 women across a river. Find the number of ways in which the group may be taken across the if all women go on the first group. - Grouping - combinatorics
In how many different ways can 24 people be divided into: a) 6 groups of the same size. b) Groups of 5, 6, 7, and 6 people. c) Groups of 4, 5, 7, and 8 people. - Probability - coin
When tossing a coin 4 times in a row, what is the probability that a sign will come up 3 times?
- Different 83538 We have four different boxes and three identical balls. Place the marbles in these boxes so that the boxes can contain one, two, three or none. How many other locations are there?
- Wardrobe code
Lucia has a lock on her wardrobe that opens with a 4-digit code (such as 0000, 0089, or 9123). Lucia forgot her code. But she knows that the sum of all four digits of her code is 4. How many such codes are there? - Married 83309
In how many ways can we seat five guests at a table, two of whom are married and want to sit next to each other? - Probability - shelf
Ten books are placed randomly on one shelf. Find the probability that certain three books are placed next to each other. - Different 82447
How many 4 colored flags can be made from 5 colors so that each flag consists of three different colors?
- Possibilities 82372
A hockey match played for three periods ended with a score of 2:3. How many possibilities are there on how the given thirds could have been completed? - Discovered 82210
At the dance party, the organizer discovered that 168 different dance pairs could be formed from girls and boys. How many boys are there at the dance if there are 12 girls? - Four-digit 82023 How many four-digit numbers are there in which there are at least three eights
- Repetition: 82003
Calculate how many different monograms (short name and surname) I can make from the letters A, E, M, Z, and K. a) with repetition: b) without repetition: - Consecutively numbers How many ways are there to arrange the numbers 3, 2, 15, 8, and 6 so that the even numbers are arranged in ascending order (not necessarily consecutively)?
- Indistinguishable 81481
How many ways can a tower of five yellow and four blue cubes be built so that each yellow cube is adjacent to at least one other yellow cube? Yellow dice are indistinguishable, and so are blue dice. - Different 79704
Thirty-two boys and 34 girls came to the dance. How many different dance pairs can they make, given that each team is given: they can only dance for 1 minute and then take turns in 5 seconds? Calculate how long the dance evening would last for all the pai - Probability 72324
When entering the PIN code, we used the digits 2, 3, 4, 5, and 7 only once. What is the probability that someone will guess our PIN code on the first try? - Groups 72194
I have eight groups. How could they place first, second, and third? - Variations 70724
If we increase the number of elements by 2, the number of variations of the second class without repetition increases by 22. How many elements do we have initially?
We have to distribute the keys to the safe among four people so that no two of them can open the safe but in such a way that any three can open the safe. How many minimum keys do we need? How to divide them? How many minimum locks must be on the safe? AllDo you have homework that you need help solving? Ask a question, and we will try to solve it. Solving math problems.
