Reason + variations - practice problems
Number of problems found: 127
- 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. - 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 82744
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
We used the digits 2, 3, 4, 5, and 7 when entering the PIN code, and we only used each digit 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? - Distribute 70244
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? All - Together 70124
Twins Ela and Nela came to the cinema together with their friend Hela. Only the first 10 seats in the third row are free. How many ways can they be seated if the twins want to sit next to each other, with Nela always to Ela's left and Hel right next to on - Michalovci 69494
How many different courses could the match between AC Michalovci and Juvent Turiec have, which ended 2:1? - Probability 68564
What is the probability that the number a) greater than 4, b) Will the number greater than four fall on the dice roll? - Divisible 67434
The number of Beata's house is 2018. The numbers of Jura's and Dan's houses are made up of the same numbers. A) What number of Jura's house can be if it is divisible by 4? List all the options. B) What can Dan's house number be if it is divisible by 5? Li
Do you have homework that you need help solving? Ask a question, and we will try to solve it.