Math Sat Ii C Tough Question

nystudent23
Sun, 02 Oct 2005 13:20:43 +0000

A craftsperson has sic different kinds of seashells. How many different bracelets can be constructed if only four shells are to be used in any one bracelet?
a) 90
b) 45
c) 60
d) 360
e) 180

Answer is 45. I know I have to use combinations but i didnt get 45.