# Combinatorics - math word problems

1. Pins 2 how many different possible 4 digits pins can be found on the 10-digit keypad?
2. PIN code PIN on Michael credit card is a four-digit number. Michael told this to his friend: • It is a prime number - that is, a number greater than 1, which is only divisible by number one and by itself. • The first digit is larger than the second. • The second.
3. Digits How many odd four-digit numbers can we create from digits: 0, 3,5,6,7?
4. A pizza A pizza place offers 14 different toppings. How many different three topping pizzas can you order?
5. Holidays with grandmam We have packed three T-shirts - white, red, orange and five pants - blue, green, black, pink and yellow. How many days can we spend with the old mother if we put on a different combination of clothes every day?
6. One three We throw two dice. What is the probability that max one three falls?
7. Bookshelf and books How many can we place 7 books in a bookshelf?
8. Family 94 boys are born per 100 girls. Determine the probability that there are two boys in a randomly selected family with three children.
9. Combinations 6 6 purses 9 flaps 12 straps Every combination must include 1 purse, 1 flap and 1 strap. How many possible combinations?
10. A book A book contains 524 pages. If it is known that a person will select any one page between the pages numbered 125 and 384, find the probability of choosing the page numbered 252 or 253.
11. Lunch Seven classmates go every day for lunch. If they always come to the front in a different order, will be enough school year to take of all the possibilities?
12. Three workplaces How many ways can we divide nine workers into three workplaces if they need four workers in the first workplace, 3 in the second workplace and 2 in the third?
13. Digit sum How many are three-digit numbers that have a digit sum of 6?
14. Sweater Dana confuses sweater and wool has a choice of seven colors. In how many ways she can choose from three colors to the sleeves?
15. The big clock The big clock hands stopped at a random moment. What is the probability that: a) a small hand showed the time between 1:00 and 3:00? b) the big hand was in the same area as a small hand in the role of a)? c) did the hours just show the time between 21:00.
16. How many How many double-digit numbers greater than 30 we can create from digits 0, 1, 2, 3, 4, 5? Numbers cannot be repeated in a two-digit number.
17. In the orchard In the orchard, they planted 25 apple trees, 20 pears, 15 plums and 40 marbles. A strong late frost, however, destroyed a fifth of all new trees. Unfortunately, it was all the trees of one kind of fruit. What is the probability that the plums have died out
18. Peaches There are 20 peaches in the pocket. 3 peaches are rotten. What is the probability that one of the randomly picked two peaches will be just one rotten?
19. Lathe 95% of the components manufactured on the lathe comply with the standard, of which 80% of the components are first-class. How likely can we expect a manufactured part to be first class?
20. Subsets How many 19 element's subsets can be made from the 26 element set?

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