a deprtment store has 8 doors. in hw many ways cn one enter and leave the store w/o passing the same door 2x?

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a deprtment store has 8 doors. in hw many ways cn one enter and leave the store w/o passing the same door 2x?

2007-11-25 22:14:05 · 4 answers · asked by icecweam 1 in Science & Mathematics ➔ Mathematics

4 answers

entry in C(8, 1) ways = 8 ways
exit in C(7, 1) ways = 7 ways
entry by one and exit by other door in
C(8, 1)*C(7, 1) = 8*7 ways = 56 ways.

2007-11-25 22:29:37 · answer #1 · answered by sv 7 · 0⤊ 0⤋

THe first response is right if after you leave you enter again...and so on until there are no more ways to enter.

3rd is right if you leave.....you don't go back in.

2007-11-26 06:48:24 · answer #2 · answered by My name is not bruce 7 · 1⤊ 0⤋

4
eight doors = 4 in + 4 out

2007-11-26 06:22:50 · answer #3 · answered by tom4bucs 7 · 0⤊ 1⤋

First, eight choices to enter.
Then, seven choices to leave.
Then, six choices to enter...
this makes 8! = 40,320 ways.

2007-11-26 06:20:39 · answer #4 · answered by Le Dave 2 · 2⤊ 1⤋