Destroyer QR #20 Probability Question

[tawaqul]

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Hi All,

Is there a way to do this problem without knowing the formula in the solution?

How many ways can 8 horses finish a race in 1st, 2nd and 3rd place?

TIA!

 

[klutzy1987]

yes, 8*7*6, which is the same thing as 8p3.

 

[td4azklz]

yes, 8*7*6, which is the same thing as 8p3.

You are wrong. 8x7x6 = 336, but 8p3 = 6720

 

[klutzy1987]

You are wrong. 8x7x6 = 336, but 8p3 = 6720

Huh, 8*7*6=336

8!/(8-3)!---->8*7*6*5!/5!

The 5! cancel out and therefore what i said is correct. Do you want to clarify your statement.

 

[Streetwolf]

He's thinking 8p3 means 8!/3! but that would be 8p5.

 

[klutzy1987]

He's thinking 8p3 means 8!/3! but that would be 8p5.

Yeah that makes sense.
To do a permutation, the formula is NpR= N!/(N-R)!

Therefore, 8p3-->8!/(8-3)!=8!/5!=8*7*6

 

[td4azklz]

Yeah that makes sense.
To do a permutation, the formula is NpR= N!/(N-R)!

Therefore, 8p3-->8!/(8-3)!=8!/5!=8*7*6

Sorry guys, yeah, now i get it.