# Examination

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

**Result****Leave us a comment of example and its solution (i.e. if it is still somewhat unclear...):**

**Showing 0 comments:**

**Be the first to comment!**

#### To solve this example are needed these knowledge from mathematics:

## Next similar examples:

- Weekly service

In the class are 20 pupils. How many opportunities have the teacher if he wants choose two pupils randomly who will weeklies? - Combinations

From how many elements we can create 990 combinations 2nd class without repeating? - Trinity

How many different triads can be selected from the group 38 students? - Fish tank

A fish tank at a pet store has 8 zebra fish. In how many different ways can George choose 2 zebra fish to buy? - Teams

How many ways can divide 16 players into two teams of 8 member? - The confectionery

The confectionery sold 5 kinds of ice cream. In how many ways can I buy 3 kinds if order of ice creams does not matter? - Confectionery

The village markets have 5 kinds of sweets, one weighs 31 grams. How many different ways a customer can buy 1.519 kg sweets. - Volleyball

8 girls wants to play volleyball against boys. On the field at one time can be six players per team. How many initial teams of this girls may trainer to choose? - Chords

How many 4-tones chords (chord = at the same time sounding different tones) is possible to play within 7 tones? - Blocks

There are 9 interactive basic building blocks of an organization. How many two-blocks combinations are there? - PIN - codes

How many five-digit PIN - code can we create using the even numbers? - Calculation of CN

Calculate: ? - Balls

The urn is 8 white and 6 black balls. We pull 4 randomly balls. What is the probability that among them will be two white? - Count of triangles

Given a square ABCD and on each side 8 internal points. Determine the number of triangles with vertices at these points. - Theorem prove

We want to prove the sentense: If the natural number n is divisible by six, then n is divisible by three. From what assumption we started? - AP - simple

Determine the first nine elements of sequence if a10 = -1 and d = 4 - Sequence 2

Write the first 5 members of an arithmetic sequence a_{11}=-14, d=-1