Question

Please help i have class soon :(

John used digits from 0 to 6 only to create a three-digit PIN code. He forgot his PIN code. He remembers that his code contains different ascending digits. What is the maximum number of combinations John has to check to find his PIN code?

Answer 1

this was incorrect.

im sorry :(

Answer 2

35

Explanation:

We know that the numbers have to be in ascending order. If, for example, the first digit is 0, and second digit is 1, then we would have 5 other numbers in the ones place that would be larger. If the second digit is 2, then would would have 4 other numbers that would be larger, and so on. So if 0 is the first digit, then we would have 5+4+3+2+1=15 combinations. If 1 is the first digit, then we would have 4+3+2+1 combinations. Eventually, we would get 35.