2007-11-25 22:17:47 · 4 answers · asked by icecweam 1 in Science & Mathematics ➔ Mathematics
20 choices for the 1st place winner.
19 choices for the 2nd place winner.
18 choices for the 3rd place winner.
20 x 19 x 18 = 6,840 ways
*Note: order *does* matter.
2007-11-25 22:21:27 · answer #1 · answered by Puzzling 7 · 0⤊ 0⤋
there is a trick to these types of questions its called combantions and permutations in this case the order 1st 2nd and 3rd ok soo you have 20 racers right and your looking in how many ways say you pick 1 guy he has 20 chance to come first when you go to the next person he has 19 chance of coming 2nd and it decreases soo use this its really useful in your calcultor put 20P3 = 6840 done :=_
2007-11-26 06:28:49 · answer #2 · answered by Anonymous · 0⤊ 0⤋
in C(20, 1)*C(19, 1)*C(18, 1) ways
= 20*19*18 ways
= 6840 ways.
2007-11-26 06:32:49 · answer #3 · answered by sv 7 · 0⤊ 0⤋
20!/(20-3)!=6840 ways
2007-11-26 06:23:37 · answer #4 · answered by someone else 7 · 0⤊ 0⤋