A suitcase lock has 4 dials with the digits 0, 1, 2,..., 9 on each. How many different settings are possible if all four digits have to be different and the combination must be greater than 7000?

Guest Jul 2, 2022

#1**0 **

There are:

10 P 4 ==5040 permutations

Since each permutations begins with one of the 10 digits, we therefore have:

5040 / 10 ==504 permutations beginning with one of the 10 digits.

Since we want all permutations >7000, we therefore should have:

**504 x 3 ==1,512 permutations > 7000.**

Guest Jul 2, 2022