How long would it take to count to a billion?
It would depend on how fast you counted.
Let's suppose, for the sake of the argument, that you could count one number every second on average. (Since most numbers in that range are something like "five hundred million, seventeen thousand, two hundred and fifty," this is being very optimistic.) In that case, it would take you a billion seconds.
Dividing that by 60 (and leaving the remainder in second form), we find that it would take 16,666,666 minutes and 40 seconds. Dividing the minutes by 60, we find it would take 277,777 hours, 46 minutes, and 40 seconds. Dividing the hours by 24, we get a new total of 11,574 days, 1 hour, 46 minutes, and 40 seconds. Finally, dividing by 365.25 (the extra quarter-day is for leap years), we end up with an approximate total of 31 years, 251 days, 7 hours, 46 minutes, and 40 seconds.
In short, if you want to count to a billion, you'd better start now.