Math Sat Ii C Tough Question

system
Sun, 02 Oct 2005 14:45:11 +0000

here’s another way of doing it

draw a picture of the bracelet, with four dots representing the shells. In the first dot, you have 6 choices of shells, in the next you have 5 choices, the next you have 4 choices, and the next you have 3. so thats 6x5x4x3 combinations, which is 360. But then, you have to divide it by 4. Why? Because you can rotate the shells around 4 times and still have the same bracelet. So then you have 90. Finally, you have to divide 90 by 2. This is because you can flip the bracelet over and it will still be the same. So your answer is 45.