how many 4 - digit numbers are there such that all 3 digits are different and the first digit and last digit is not zero ?
Pick:
A) 2128  B) 3458  C) 4207  D) 5184  E) 8104

Rationale: all three digits are different and first digit is not zero . so first digit can be filled in 8 ways . and , second digit can be filled in 9 ways . and , third digit can be filled in 9 ways . and , fourth digit can be filled in 8 ways . total ways = 8 * 9 * 9 * 8 = 5184 hence option ( d ) .
Answer: D