i. • passwords may only contain lowercase letters • passwords must be exactly 5 characters long ii. • passwords may only contain lowercase letters • passwords may be between 5 and 7 characters long iii. • passwords may only contain lowercase letters • passwords may be between 5 and 7 characters long • passwords may not start with the letters a, b or c
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 passwords can be created which meet each set of criteria below? Use the counting unions method, counting cartesian product or pigeon principle method to get the answer
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