Posted by Allison on Sunday, May 6, 2007 at 2:18pm.
Keiko has 7 colors of lanyard. She uses 3 different colors to make a keychain. How many different combinations can she choose?
7 for the first, 6 for the second and 5 for the third. The answer is the product of those numbers, no matter what order the three colors are picked. The number of possibilities in "combination" problemsa like this can written in the form
7!/(73)! = 7!/4! = 7x6x5
Write out the possibilities.
All of them.
Then count them.
Tada! Ur answer will appear.
:D

Math  Anonymous, Tuesday, April 5, 2016 at 5:18pm
28