List all combinations of the letters ABCD in groups of 3. There are only four combinations [ABC, ABD, ACD, and BCD].
How many combinations are possible while selecting four letters from the word Smokejack?
41 combinations are possible while selecting four letters from the word ‘smokejack’ with the condition that ‘j’ must appear in it.
How many combinations are there with 4 numbers and letters?
If we assume your letters range from A to Z and your digits from 0 to 9, you have 26 possibilities per letter and 10 per digit. This gives you 26^4*10^4 which is roughly 4 billion and a half. I would say – without much thinking – 26^4 * 10000, if the order is given: 4 letters and 4 digits.
How many combinations of 4 items have no repeats?
The number of possible combinations with 4 numbers without repetition is 15.
How many words can you make out of combination?
Combination is a 11 letter long Word starting with C and ending with N. Below are Total 240 words made out of this word. 1]. amniotic 2]. amnionic 3]. bionomic 4]. mannitic 5]. inaction 6]. ambition 7]. conation 8]. monition
How many words can you make out of random?
66 words can be made from the letters in the word random. This page is a list of all the words that can be made from the letters in random, or by rearranging the word random. These words should be suitable for use as Scrabble words, or in games like Words with friends.
How many words can you make out of Shuffle?
Shuffle is a 7 letter medium Word starting with S and ending with E. Below are Total 47 words made out of this word. 1]. flues 2]. luffs 3]. fuels 4]. shelf 5]. huffs 6]. flesh 7]. sluff 8]. flush 9]. fusel
How many combinations can be made with four numbers?
There are 10,000 combinations of four numbers when numbers are used multiple times in a combination. There are 5,040 combinations of four numbers when numbers are used only once. There are 10 choices, zero through nine, for each number in the combination.
The number of ways of arranging n unlike objects in a line is n! [pronounced ‘n factorial’]. n! = n × [n – 1] × [n – 2] ×…× 3 × 2 × 1
Example
How many different ways can the letters P, Q, R, S be arranged?
The answer is 4! = 24.
This is because there are four spaces to be filled: _, _, _, _
The first space can be filled by any one of the four letters. The second space can be filled by any of the remaining 3 letters. The third space can be filled by any of the 2 remaining letters and the final space must be filled by the one remaining letter. The total number of possible arrangements is therefore 4 × 3 × 2 × 1 = 4!
The number of ways of arranging n objects, of which p of one type are alike, q of a second type are alike, r of a third type are alike, etc is:
n! .
p! q! r! …
Example
In how many ways can the letters in the word: STATISTICS be arranged?
There are 3 S’s, 2 I’s and 3 T’s in this word, therefore, the number of ways of arranging the letters are:
10!=50 400
3! 2! 3!
Rings and Roundabouts
- The number of ways of arranging n unlike objects in a ring when clockwise and anticlockwise arrangements are different is [n – 1]!
When clockwise and anti-clockwise arrangements are the same, the number of ways is ½ [n – 1]!
Example
Ten people go to a party. How many different ways can they be seated?
Anti-clockwise and clockwise arrangements are the same. Therefore, the total number of ways is ½ [10-1]! = 181 440
Combinations
The number of ways of selecting r objects from n unlike objects is:
Example
There are 10 balls in a bag numbered from 1 to 10. Three balls are selected at random. How many different ways are there of selecting the three balls?
10C3 =10!=10 × 9 × 8= 120
3! [10 – 3]!3 × 2 × 1
Permutations
A permutation is an ordered arrangement.
The number of ordered arrangements of r objects taken from n unlike objects is:
nPr = n! .
[n – r]!
Example
In the Match of the Day’s goal of the month competition, you had to pick the top 3 goals out of 10. Since the order is important, it is the permutation formula which we use.
10P3 =10!
7!
= 720
There are therefore 720 different ways of picking the top three goals.
Probability
The above facts can be used to help solve problems in probability.
Example
In the National Lottery, 6 numbers are chosen from 49. You win if the 6 balls you pick match the six balls selected by the machine. What is the probability of winning the National Lottery?
The number of ways of choosing 6 numbers from 49 is 49C6 = 13 983 816 .
Therefore the probability of winning the lottery is 1/13983816 = 0.000 000 071 5 [3sf], which is about a 1 in 14 million chance.