# High school + combinatorial number - examples

- A student

A student is to answer 8 out of 10 questions on the exam. a) find the number n of ways the student can choose 8 out of 10 questions b) find n if the student must answer the first three questions c) How many if he must answer at least 4 of the first 5 que - Families 2

There are 729 families having 6 children each. The probability of a girl is 1/3 and the probability of a boy is 2/3. Find the the number of families having 2 girls and 4 boys. - Word

What is the probability that a random word composed of chars T, H, A, M will be MATH? - Chocolates

In the market have 4 kinds of chocolates. How many ways can we buy 19 chocolates? - 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? - N-gon

How many diagonals has convex 11-gon? - 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? - Party

At party overyone clink with everyone. Together, they clink 171 times. How many people were at the party? - 2nd class combinations

From how many elements you can create 4560 combinations of the second class? - Lines

In how many points will intersect 14 different lines, where no two are parallel? - 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? - Family

What is the probability that a family with 7 childrens have: exactly 5 girls? 7 girls and 0 boys? Consider the birth probability of a girl is 48.69% and boy 51.31%. - Bulbs

The probability that the bulb can operate 5000 hours is 0.16. What is the probability that exactly one of three bulbs can operate 5000 hours? - Examination

The class is 21 students. How many ways can choose two to examination? - 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 - Tournament

Determine how many ways can be chosen two representatives from 34 students to school tournament. - Cinema

How many ways can be divided 11 free tickets to the premiere of "Jáchyme throw it in the machine" between 6 pensioners? - 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? - Circles

How many different circles is determined by 9 points at the plane, if 6 of them lie in a straight line? - Three-digit numbers

How many three-digit numbers are from the numbers 0 2 4 6 8 (with/without repetition)?

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