To avoid using Combination or Permutation notation, you can always just consider the following steps to manually calculate the scenario:

1) Draw a ____ for Each Selection to be Made and Label any Dictated Restrictions for the Selection.

In this Case there will be a selection of two doors:

Door 1 and

Door 22) Determine Most Efficient Method to Properly and Specifically Make Selection based on Problem and Consider Whether Selecting this or That.

In this Case the First door Selection Impacts the Second Door Selection So We Need to Split into Two Scenarios:

Door 1 (Red) and

Door 2 (Green) OR

Door 1 (Green) and

Door 2 (Red)3) Then Insert the Number or Available Options to Select at Moment of Selection One Blank at a Time

In this Case for the first iteration:

2 options (Red) and

3 options (Green) OR

3 options (Green) and

2 options (Red)4) Finally, calculate. When Selecting This AND That - Multiply. So, in the first iteration there are 2 x 3 = 6 ways to enter a Red door and exit a Green door as well as 3 x 2 = 6 ways to enter a Green door and exit a Red door in the second iteration. Then, when it is possible to Select this OR That - Add. So, add the 6 ways to proceed Red then Green to the 6 ways to proceed Green then Red to determine that there are 12 total ways to enter one color door and exit the other.

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Stefan Maisnier

Director of Online Tutoring, MyGuru

www.myguruedge.com

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