Math, asked by Sandraanne, 1 month ago

xPx-1 = 6
P = Permutation
With Solution Please

Answers

Answered by user0888
4

Before we solve

The question is asking us, "can you use the definition of permutation?" We have to change _xP_{x-1} into the form that we can solve.

Keys

  • Permutation

A permutation is the number of ways to line up r people, from n people.

\boxed{_nP_r=\dfrac{n!}{(n-r)!}}

Solution

Here, \bold{n=x,r=x-1}.

First things first,

_xP_{x-1}=\dfrac{x!}{\{x-(x-1)\}!} =\boxed{\dfrac{x!}{1!} }

So, we have,

x!=3!

Then,

\therefore \boxed{x=3}

More information

  • Combination

A combination is the number of ways to choose r quantities, from n quantities.

To derive the combination, we simply remove the same possibilities that happen from changed orders.

\boxed{_nC_r=\dfrac{_nP_r}{(n-r)!} =\dfrac{n!}{r!(n-r)!} }

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