# Combinatorial number + multiplication principle - examples

1. Word What is the probability that a random word composed of chars T, H, A, M will be the MATH?
2. Rectangles How many rectangles with area 3032 cm2 whose sides is natural numbers are?
3. Candy How many ways can divide 16 identical candies to 4 children?
4. 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?
5. 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?
6. 2nd class combinations From how many elements you can create 4560 combinations of the second class?
7. Commitee A class consists of 6 males and 7 females. How many committees of 7 are possible if the committee must consist of 2 males and 5 females?
8. Math logic There are 20 children in the group, each two children have a different name. Alena and John are among them. How many ways can we choose 8 children to be among the selected A) was John B) was John and Alena C) at least one was Alena, John D) maximum one w
9. Cinema How many ways can be divided 11 free tickets to the premiere of "Jáchyme throw it in the machine" between 6 pensioners?
10. The camp At the end of the camp a 8 friends exchanged addresses. Any friend gave remaining 7 friends his card. How many addresses they exchanged?
11. Three-digit numbers How many three-digit numbers are from the numbers 0 2 4 6 8 (with/without repetition)?
12. Combinatorics The city has 7 fountains. Works only 6. How many options are there that can squirt ?
13. Hockey Hockey match ended 8:2. How many different matches could be?
14. Weekly service In the class are 20 pupils. How many opportunities have the teacher if he wants choose two pupils randomly who will weeklies?
15. travel agency Small travel agency offers 5 different tours at honeymoon. What is the probability that the bride and groom choose the same tour (they choose independently)?
16. Count of triangles Given a square ABCD and on each side 8 internal points. Determine the number of triangles with vertices at these points.
17. Hockey game In the hockey game was made 6 goals. Czech played against Finland. Czechs won 4:2. In what order to fall goals? How many game sequence was possible during the game?
18. Salami How many ways can we choose 5 pcs of salami, if we have 6 types of salami for 10 pieces and one type for 4 pieces?
19. Sum or product What is the probability that two dice fall will have the sum 7 or product 12?
20. Class pairs In a class of 34 students, including 14 boys and 20 girls. How many couples (heterosexual, boy-girl) we can create? By what formula?

Do you have an interesting mathematical example that you can't solve it? Enter it, and we can try to solve it.

To this e-mail address, we will reply solution; solved examples are also published here. Please enter e-mail correctly and check whether you don't have a full mailbox.