While driving down Interstate 71 at a constant rate of speed, Malaz passes a milepost with a 2-digit number. Exactly one hour later he passes a milepost with the same two digits, but they're reversed. And exactly one hour after that he passes a third milepost with the same two digits (backward or forward) with a zero in between them. What is the number on the first milepost, and how fast is he going? (Note: he did not start driving at mile 0.)

## Solution

16, 61, 106; 45 mph