If each of 3 digit code is formed of integers from 1 to 20, inclusively, and each of the digits are different, how many possible codes are there?  Choose the correct choice from the following.
A) 6,040
B) 6,840
C) 6,240
D) 6,340
E) 8,440
Code consists of 3 digits and no digit is repeated.   First digit of the code can have 20 possibilities   Second digit can have 19 possibilities   Third digit can have 18 possibilities   Total number of possible codes = 20*19*18= 
<gadget id="calculator">20*19*18</gadget>
<output>6_840</output>
6840   Answer: 6,840
<result>B</result>
If each of 3 digit code is formed of integers from 1 to 20, inclusively, and each of the digits are different, how many possible codes are there?