How many permutations of the letters ABCDEFGH contain the string CFA?
Permutations and Combinations
If there are 5 dishes, they can be relished in any order at a time. In permutation, it should be in a particular order. In combination, the order does not matter. Take 3 letters a, b, and c. The possible ways of pairing any two letters are ab, bc, ac, ba, cb and ca. It is in a particular order. So, this can be called the permutation of a, b, and c. But if the order does not matter then ab is the same as ba. Similarly, bc is the same as cb and ac is the same as ca. Here the list has ab, bc, and ac alone. This can be called the combination of a, b, and c.
Counting Theory
The fundamental counting principle is a rule that is used to count the total number of possible outcomes in a given situation.
How many permutations of the letters ABCDEFGH contain the string CFA?
We need to find the number of permutations of the letters ABCDEFGH that contain the string CFA.
We need to use permutations.
If we have n objects and we need to find the number of permutation of n objects taken r at a time then
Now, we have the letters ABCDEFGH . It has 8 letters.
We need to find the number of permutations of these letters that contain the string CFA.
This means that we need to take letters CFA always together and in the same order.
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