The amount of water in a tank doubles every minute. If the tank was full at the 1 hour mark, when was the tank half full? ============================= It's not homework, I'm just trying to get the actual (reasoned) answer.. ============================= Here is the answer I argued (though, I'm not sure): 2^x = [(2^59)/2] 2^x = 2^58 x = 58 ============================= But, almost everyone argues: If it doubles every minute, isn't it half full the minute before it's full? ie. 59 ============================= Pretty sure I'm incorrect, I just want to know for sure..