# Combinatorics - math word problems

#### Number of problems found: 405

• 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?
• Events
Event P has probability of 0.84. What is the probability that the event P occurs in 3, 5, 7 try.
• Pediatrician
Pediatrician this month of 20 working days takes 8 days holidays. What is the probability that on Monday it will be at work?
• TV fail
The TV has after 10,000 hours average 35 failures. Determine the probability of TV failure after 400 hours of operation.
• Lines
In how many points will intersect 14 different lines, where no two are parallel?
• 7 heroes
9 heroes galloping on 9 horses behind. How many ways can sort them behind?
• 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 th
• Rectangle
In a rectangle with sides, 8 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?
• Raffle
In the pool is numbers from 1 to 115. What is the probability that a randomly selected number is not a prime number?
• Hockey
The hockey match ended 8:2. How many different matches could be?
• Calculation of CN
Calculate: (789 choose 786) - (789 choose 3)
• Subsets
How many are all subsets of set C = (97, 67, 66, 18, 59, 64)?
• Word
What is the probability that a random word composed of chars E, Y, G, E, R, O, M, T will be the GEOMETRY?
• Bulbs
In the box are 6 bulbs with power 75 W, 14 bulbs with power 40 W and 15 with 60 W. Calculate probability that a randomly selected bulb is:
• Rectangles
How many rectangles with area 8713 cm2 whose sides are natural numbers are?
• Flags
How many different flags can be made from colors red, yellow, blue, green, white to consist of three different colors?
• Shooter
The probability that a good shooter hits the center of the target circle I is 0.1. The probability that the target hit intercircle is II 0.58. What is the probability that it hits the target circle I or II?
• Shooters
In army regiment are six shooters. The first shooter target hit with a probability of 49%, next with 75%, 41%, 20%, 34%, 63%. Calculate the probability of target hit when shooting all at once.
• Event probability
The probability of event P in 8 independent experiments is 0.33. What is the probability that the event P occurs in one experiment (chance is the same)?
• Bulbs
The probability that the bulb can operate 4000 hours is 0.3. What is the probability that exactly one of eight bulbs can operate 4000 hours?

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