If each of 4 digit code is formed of integers from 1 to 10, inclusively, and each of the digits are different, how many possible codes are there? Pick one.
A) 6,040	B) 6,840	C) 6,240	D) 5,040	E) 4,069
Code consists of 4 digits and no digit is repeated.   First digit of the code can have 10 possibilities   Second digit can have 9 possibilities   Third digit can have 8 possibilities   Total number of possible codes = 10*9*8*7= 
<gadget id="calculator">10*9*8*7</gadget>
<output>5_040</output>
5040   Answer: 5,040
<result>D</result>
If each of 4 digit code is formed of integers from 1 to 10, inclusively, and each of the digits are different, how many possible codes are there?