# Combinatorics - problems

Would you like to compute count of combinations?- Test

The teacher prepared a test with ten questions. The student has the option to choose one correct answer from the four (A, B, C, D). The student did not get a written exam at all. What is the probability that: a) He answers half correctly. b) He answers. - Desks

A class has 20 students. The classroom consists of 20 desks, with 4 desks in each of 5 different rows. Amy, Bob, Chloe, and David are all friends, and would like to sit in the same row. How many possible seating arrangements are there such that Amy, Bob, C - Red balls

In the bag there are 3 red, 12 blue and 8 green balls. How many red balls we must be attached to the bag if we want the probability of pulling out the red balls was 20%? - No. of divisors

How many different divisors has number ?? - Rectangle

In rectangle with sides 10 and 9 mark the diagonal. What is the probability that a randomly selected point within the rectangle is closer to the diagonal than to any side of the rectangle? - 7 heroes

5 heroes galloping on 5 horses behind. How many ways can sort them behind? - Ace

From complete sets of playing cards (32 cards) we pulled out one card. What is the probability of pulling the ace? - Flags

How many different flags can be made from colors white, yellow, red, blue, green, orange so that each flag consisted of three different colors? - Vans

In how many ways can 8 shuttle vans line up at the airport? - Seating

How many ways can 7 people sit on 3 numbered chairs (eg seat reservation on the train)? - Pediatrician

Pediatrician this month of 21 working days takes 3 days holidays. What is the probability that on Monday will be at work? - Bureau of Labor

Bureau of Labor is a state institution that provides mike and the rest for their so-called clients. The mission of the Bureau of Labor is spend taxpayer money to provide relaxation and benefits to those who do not want to work. Popularly speaking sense the - Guests

How many ways can 7 guests sit down on 9 seats standing in a row? - 2nd class variations

From how many elements you can create 6480 variations of the second class? - Word

What is the probability that a random word composed of chars M, R, P, E, I, O, G, S, S, G, R, T, E, C, E, N, I, O, O, R will be GEOMETRICPROGRESSION? - Shelf

How many ways are there to arrange 9 books on a shelf? - Phone numbers

How many 9-digit telephone numbers can be compiled from the digits 0,1,2,..,8,9 that no digit is repeated? - Chocolates

In the market have 3 kinds of chocolates. How many ways can we buy 13 chocolates? - Rectangles

How many rectangles with area 2832 cm^{2}whose sides is natural numbers are? - Two doctors

Doctor A will determine the correct diagnosis with a probability 80% and doctor B with a probability 72%. Calculate probability of correct diagnosis if patient is diagnosed by both doctors.

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