Patrick has a lock that contains a 3 digit password. He forgets the combination, but knows that he only used prime numbers for each digit in the combination and he did not repeat any numbers. How many different passwords could he possibly try before opening the briefcase? Choices:
A) 6
B) 12
C) 15
D) 18
E) 24
Permutation calc is: n P r = n! / (n-r)! 4 P 3 = 4!/(4-3)! = 4x3x2x1/1!4 /(4-3)= 
<gadget id="calculator">4 /(4-3)</gadget>
<output>4</output>
4x3x2x1/1!=24/1= 
<gadget id="calculator">24/1</gadget>
<output>24</output>
24 Correct answer is 24 (24)
<result>E</result>
Patrick has a lock that contains a 3 digit password. He forgets the combination, but knows that he only used prime numbers for each digit in the combination and he did not repeat any numbers. How many different passwords could he possibly try before opening the briefcase?