Mathematics: Sara has six necklaces, but her mother will only allow her to wear two at a time. how many different combinations of two necklaces can sara wear?

Sara has six necklaces, but her mother will only allow

rfultz27

12.03.2022

15 different combinations

Step-by-step explanation:

Sara has six necklaces, but her mother will allow her to wear two at a time.

So we calculate different combinations of two necklaces by this formula:

$\frac{n!}{r!(n-r)!}$

Where n = 6 and r = 2

Now put the values

$\frac{6!}{2!(6-2)!}$

$\frac{6\times 5\times 4\times 3\times 2\times 1}{2!(6-2)!}$

$\frac{720}{2\times 1(4)!}$

$\frac{720}{2\times 1(4\times 3\times 2\times 1)}$

$\frac{720}{2(24)}$

$\frac{720}{48}$ = 15 combinations

Sara can wear 15 different combinations of two necklaces.

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fefebat

13.07.2022

$\bold{M_{AB}\left(\frac12\,,\ 1\right)}$

Step-by-step explanation:

The midpoint of AB coordinates are: $M_{AB}\left(x_M\,,\ y_M\right)$ where:

$x_M=\frac{x_A+x_B}2=\frac{-1+2}2=\frac12\\\\y_M=\frac{y_A+y_B}2=\frac{5+(-3)}2=\frac{2}2=1$

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