Factorial - practice problems
The factorial of the number n is the product of the first n natural numbers. For example 6! (we read 6 factorial) is 1*2*3*4*5*6 = 720.
Direction: Solve each problem carefully and show your solution in each item.
Number of problems found: 138
- Factorial divisible by 75  Find the least positive integer n such that n! is divisible by 75. Find the least positive integer n such that n! is divisible by 75.
- Five couples  In how many ways can 5 couples arrange themselves in a row if they stay together? In how many ways can 5 couples arrange themselves in a row if they stay together?
- Student examination  How many ways can a teacher select a group of 6 students to sit in the front row if the class has 13 students? How many ways can a teacher select a group of 6 students to sit in the front row if the class has 13 students?
- Footballers 2  Footballers have jerseys with numbers 7, 8, 9, 10, 11. The coach wants to send them to attack a) so that even jersey numbers are not next to each other b) so that odd jersey numbers are not next to each other. How many options does he have? Footballers have jerseys with numbers 7, 8, 9, 10, 11. The coach wants to send them to attack a) so that even jersey numbers are not next to each other b) so that odd jersey numbers are not next to each other. How many options does he have?
- In the library  We have 8 different books in the library. How many ways can they be arranged? How many possibilities are there if 3 volumes are to be in a certain order? How many possibilities are there if three volumes are to be in a row independently in order? We have 8 different books in the library. How many ways can they be arranged? How many possibilities are there if 3 volumes are to be in a certain order? How many possibilities are there if three volumes are to be in a row independently in order?
- Birthday boy 2  In how many ways can seven people be seated around a table so that the birthday boy sits at the head? In how many ways can seven people be seated around a table so that the birthday boy sits at the head?
- HAMMER 3  Determine how many ways it is possible to rearrange the letters of the word HAMMER so that in this rearrangement some group of consecutive letters forms the word WATER. Determine how many ways it is possible to rearrange the letters of the word HAMMER so that in this rearrangement some group of consecutive letters forms the word WATER.
- Relay  The relay race will be run for the class of Katka, Alice, Michaela, and Erika. Determine how many different orders there are in which the girls can run, as long as each of them can run in any position. The relay race will be run for the class of Katka, Alice, Michaela, and Erika. Determine how many different orders there are in which the girls can run, as long as each of them can run in any position.
- 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. 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.
- Refrigerator, lemonades  How many possible ways can we store three lemonades, four mineral waters, and two juices in the refrigerator next to each other? How many possible ways can we store three lemonades, four mineral waters, and two juices in the refrigerator next to each other?
- Married pairs  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? 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?
- Cancel variations  Evaluate the following expression with factorials: (45!-44!)/(44!) Evaluate the following expression with factorials: (45!-44!)/(44!)
- Probability - shelf  Ten books are placed randomly on one shelf. Find the probability that certain three books are placed next to each other. Ten books are placed randomly on one shelf. Find the probability that certain three books are placed next to each other.
- Permutations 82516  From how many elements can we make 5040 permutations without repetition? From how many elements can we make 5040 permutations without repetition?
- Different 82447  How many 4 colored flags can be made from 5 colors so that each flag consists of three different colors? How many 4 colored flags can be made from 5 colors so that each flag consists of three different colors?
- Aquaristics  We consider “words” (i.e. arbitrary strings of letters) obtained by rearranging the letters of the word “AQUARISTICS”. All letters are distinguishable from each other here. The number of such words that also contain the expression “CAVA” (as consecutive l We consider “words” (i.e. arbitrary strings of letters) obtained by rearranging the letters of the word “AQUARISTICS”. All letters are distinguishable from each other here. The number of such words that also contain the expression “CAVA” (as consecutive l
- SKMO  Petra had written natural numbers from 1 to 9. She added two of these numbers, deleted them, and wrote the resulting sum instead of the summaries. She thus had eight numbers written down, which she managed to divide into two groups with the same product. Petra had written natural numbers from 1 to 9. She added two of these numbers, deleted them, and wrote the resulting sum instead of the summaries. She thus had eight numbers written down, which she managed to divide into two groups with the same product.
- Natural numbers  Find the number of all natural numbers greater than 200 in which the digits 1, 2, 4, 6, 8 occur at most once and not contains any other digits. Find the number of all natural numbers greater than 200 in which the digits 1, 2, 4, 6, 8 occur at most once and not contains any other digits.
- Indistinguishable 74294  We have eight compartments where we put three indistinguishable balls and two distinguishable ones. How many options do we have? We have eight compartments where we put three indistinguishable balls and two distinguishable ones. How many options do we have?
- Parking  72644   How many ways can ten cars park side by side in a parking lot? How many ways can ten cars park side by side in a parking lot?
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