AAPL wrote:Which of the following leads to the correct mathematical solution for the number of ways that the letters of the word BANANA could be arranged to create a six-letter code?
A. 6!
B. 6! - (3! + 2!)
C. 6! - (3! x 2!)
D. 6! / (3! + 2!)
E. 6! / (3! x 2!)
This problem does indeed require that we count the number of possible arrangements.
BANANA = 6 letters.
The number of ways to arrange 6 distinct elements = 6!.
But the elements here are not all distinct.
There are 3 identical A's and 2 identical N's.
When an arrangement includes identical elements, we must divide by the number of ways each set of identical elements can be arranged.
The reason:
When the identical elements swap places, the arrangement does not change, reducing the total number of unique arrangements.
Here, we must divide by 3! to account for the 3 identical A's and by 2! to account for the 2 identical N's:
6!/(3!2!).
The correct answer is
E.
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