# Combinatorics - examples

- Cancel fractions

Compress the expression of factorial: (n+6)!/(n+4)!-n!/(n-2)! - Normal distribution GPA

The average GPA is 2.78 with a standard deviation of 4.5. What are students in the bottom the 20% having what GPA? - No. of divisors

How many different divisors has number ?? - Rectangle

In rectangle with sides 3 and 10 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 red, blue, green, white, yellow so that each flag consisted of three different colors? - Vans

In how many ways can 5 shuttle vans line up at the airport? - Seating

How many ways can 7 people sit on 2 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 8 guests sit down on 10 seats standing in a row? - 2nd class variations

From how many elements you can create 6972 variations of the second class? - Word

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

How many ways are there to arrange 6 books on a shelf? - Chocolates

In the market have 4 kinds of chocolates. How many ways can we buy 23 chocolates? - Phone numbers

How many 7-digit telephone numbers can be compiled from the digits 0,1,2,..,8,9 that no digit is repeated? - Two doctors

Doctor A will determine the correct diagnosis with a probability 92% and doctor B with a probability 88%. Calculate probability of correct diagnosis if patient is diagnosed by both doctors. - Rectangles

How many rectangles with area 3002 cm^{2}whose sides is natural numbers are? - Football league

In the 5th football league is 10 teams. How many ways can be filled first, second and third place?

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