The above problem can be written as permutation P (4.2), n (number of teachers) = 4 k (number of positions) = 2
enter into the formula:
P (4,2) = 4! [1945909] = 4 x 3 x 2 x 1 = 24 = 12
Sample Problem 2
How many numbers are formed from 2 different numbers that we can construct from the order of the numbers 4, (19459015)
Discussion:
The above question can be concluded as a permutation consisting of 2 elements selected from 5 elements it can be written as P (5,2). Live we enter into the formula.
P (5,2) = 5! [194590]] 120 = 20
(5-2 )! 3 x 2 x 1 6
Then there are 20 ways that can be done to synthesize these numbers into 2 different numbers (48 , 42, 43, 45, 84, 82, 83, 85, 53, 52, 52, 52, 52, 52).
Combination
combinations are a collection of some or all of the objects with no regard to their order. In combination, AB is considered to be the same as BA so that a combination of two identical objects can not be repeated.
The formula of combinations of a set having n elements can be written as follows:
[1945907] Combination formula
C ( n , R ) = n C r = n C r = n!
r! (Nr)!
Let us observe the use of the formula to solve the following problems:
Sample Problem 3
Manuel Pelegrini brought 16 players at Manchester City against Liverpool at Etihad Stadium. 11 of them will be selected to play in the first half. If we do not pay attention to the player's position, how many ways can the coach take to choose a player?
Discussion:
Emphasizing the player's position, then we use the combination formula:
16 C 11 = 16! [194590]] 16 x 15 x 14 x 13 x 12 x 11!
11! (16-11)! 11! 5!
= 524160 = 5 x 4 x 3 x 2 x 1 120
] [194590]
Example Problem 4
A bucket containing 1 avocado, 1 pear, 1 orange and 1 salak. How many combinations are composed of three kinds of fruit?
[1945907]
Discussion:
known n = 4 and R = 3, then:
4 C 3 = 4! 24 = 4 3! (4-3)! 3! 1! 3 x 2 x 1 6
Okay, now you must have understood about here before the discussion of material Differences in Permutations and Combinations of Mathematics, Sample Problems and Complete Discussion for this occasion. Please refer to other mathematics lesson material in this blog to increase your knowledge about mathematics.
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