I am having trouble understanding the problem on page 39 of the FDP guide. I see why statement 1 is insufficient but can't completely see why statement 2 is sufficient.

Based on the explanation provided, there are multiple numbers which satisfy statement 2: 45, 65, etc.

If this is the case, then how can it be sufficient with more than one possible answer for x? Or is the question simply, once statement 2 has been satisfied, that the units digit of the "test number(s)" be the same regardless of the number?