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A​ golf-course architect has five linden​ trees, three white birch​ trees, and two bald cypress trees to plant in a row along a fairway. In how many ways can the landscaper plant the trees in a​ row, assuming that the trees are evenly​ spaced?

Respuesta :

Answer: 2520

Explanation

To find the number of ways to arrange something, use factorial (symbol: !) This will multiply the number and all the numbers below it.

E.g. 4! = 4×3×2×1 = 24, which is the number of ways you can arrange 4 objects.

Hence, since there are 10 trees, 10! = 3628800

However, the trees are not unique. This means that some of the trees are the same - like the 'two bald cypress trees'. To fix this, we need to divide by the numbers of non-unique trees (to get rid of duplicates):

[tex]\frac{10!}{5!*3!*2!}[/tex]

(5 linden trees, 3 white birch trees, 2 bald cypress trees)

This will give us the final answer of 2520

(Note: to use factorial on a casio scientific caluclator, press [SHIFT] + [x⁻¹] )

Using arrangements, it is found that the threes can be planted in 2520 ways.

The number of possible arrangements of n elements is given by:

[tex]A_n = n![/tex]

If these elements repeat [tex]n_1, n_2, ..., n_n[/tex] times, we have that:

[tex]A_n^{n_1, n_2, ..., n_n} = \frac{n!}{n_1!n_2!...n_n!}[/tex]

In this problem, there are 10 trees, thus [tex]n = 10[/tex].

They repeat 5, 3 and 2 times, thus [tex]n_1 = 5, n_2 = 3, n_3 = 2[/tex].

Then:

[tex]A_{10}^{5,3,2} = \frac{10!}{5!3!2!} = 2520[/tex]

There are 2520 ways to plant the trees.

A similar problem is given at https://brainly.com/question/24648661