Answer :
840 are 4-letter passwords can be formed using the letters by permutation .
What are some examples of permutation?
- A permutation is a set up of things in a specific order. In this arrangement, the components or components of sets are organized in a linear or sequential order.
- The permutation of the set A=1,6 is 2, for instance, 1,6, and 6,1.
- The components of set A cannot be arranged in any other way, as you can see.
We are to count all possible 4-letter passwords that can be generated from the letters a, b, c, d, e, f, g .
There are 7 letters in total.
n = 7 r = 4
P(n , r ) = 7!/( n - r )!
P( 7 ,4 ) = 7!/( 7 - 4)!
= 7!/3!
= 7 * 6 * 5 * 4 * 3 * 2 * 1/3!
= 7 * 6 * 5 * 4
= 840
Learn more about permutation
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