How many 3 digit positive integers with distinct digits are there, which are not multiples of 10?
Choose the correct choice from the following choices:
A) 576
B) 520
C) 504
D) 432
E) 348

Rationale: a number not to be a multiple of 10 should not have the units digit of 0 . xxx 9 options for the first digit ( from 1 to 9 inclusive ) . 8 options for the third digit ( from 1 to 9 inclusive minus the one we used for the first digit ) . 8 options for the second digit ( from 0 to 9 inclusive minus 2 digits we used for the first and the third digits ) 9 * 8 * 8 = 576 . answer : a .
Answer: A