Combinatorics - examples - page 11
- Combinations 6
6 purses 9 flaps 12 straps Every combination must include 1 purse, 1 flap and 1 strap. How many possible combinations?
- Digit sum
How many are three-digit numbers that have a digit sum of 6?
- 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.
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?
How many 19 element's subsets can be made from the 26 element set?
- 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.
Dana confuses sweater and wool has a choice of seven colors. In how many ways she can choose from three colors to the sleeves?
- 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
- Dinning room
How many different combinations can we choose if there are 3 soups, 5 kinds of main dish and 2 desserts in the dining room?
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
- Prime number
Jan wrote any number from 1 to 20. What is the probability that he wrote the prime number?
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?
- Bridge cards
How many bridge hands are possible containing 4 spades,6 diamonds, 1 club, and 2 hearts?
- Cancel fractions
Compress the expression of factorial: (n+6)!/(n+4)!-n!/(n-2)!
- Inverted nine
In the hotel,, Inverted nine" each hotel room number is divisible by 6. How many rooms we can count with three-digit number registered by digits 1,8,7,4,9?
- To improve
To improve her handwriting Paula practices writing the numbers 1 to 200 in words. How many times will she have written the word "one" in all?
- How many 2
How many three lettered words can be formed from letters A B C D E G H if repeats are: a) not allowed b) allowed
There are 9 interactive basic building blocks of an organization. How many two-blocks combinations are there?
- Find the 2
Find the term independent of x in the expansion of (4x3+1/2x)8
- Combinations 7
A multi-course meal has 3 choices. 3 appetizers, 4 main courses, and 3 desserts. How many different combinations to choose from?
Would you like to compute count of combinations?