Shirts and PantsDate: 08/29/97 at 22:01:42 From: \The Spark Plug\ Subject: Combinations Ed has 6 new shirts and 4 new pairs of pants... How many combinations of shirts and pants does he have? Is there a formula? I was using 6! and 4! but don't know what to with it! Date: 08/31/97 at 18:49:35 From: Doctor Guy Subject: Combinations >Is there a formula? Yes, there is. Allow me to explain how it is derived. Let's call the shirts A,B,C,D,E, and F and the pants w,x,y, and z. If Ed chooses shirt A, then what pants could he wear? Any of them, so he could wear as follows: Aw, or Ax, Ay, Az. That is 4 combinations. We are now finished with shirt A, so let's look at shirt B. He again could choose any of the 4 pants, getting Bw,Bx,By, or Bz. That is again 4 combinations. It would be boring, but we could continue with shirt C, shirt D, shirt E, and shirt F. Obviously for each shirt, he has 4 pants to choose from. I hope you can see the shortcut: just multiply the number of shirts times the number of pants. Now if he also had 7 different pairs of socks and 3 pairs of shoes, and he didn't care what color went with what (some people do care), then the total number of combinations would be (no. of shirts) * (no. of pairs of pants) * (no. of pairs of socks) * (no. of pairs of shoes). -Doctor Guy, The Math Forum Check out our web site! http://mathforum.org/dr.math/ |
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