I dunno about the sec. time played but..
The time played depends on how much u've played. I'll take some random numbers to show you.
Okay.. 3 hours and you're level 45. So. 3 hr = 180mins = 10800 seconds
so. if you want to be level 70, thats 25 levels more. thinking about it, that's about half of 45(approximations, since it just doesn't have to be obvious).
soz, 10800+1/2(10800) = time played recommended by me..
same concept. remember that each level takes more time.