Is going AFK acceptable when you are being inted?

So I'm a very long time league player as I've been playing since season 2. As of now I'm much older and don't have a lot of time to play League of Legends. I've also never gone afk before accept for 1-2 emergencies that have occurred in my life. My question is regarding being inted. This got me thinking because recently I was playing a game as adc, which I enjoy playing but my support decided early in the game she wanted to troll the entire time. She was playing Janna and would just walk under the tower and die over and over. Also would dance and "forget" to use any abilities if a fight broke out. The issue comes when I only get to play 1-2 games if I get the free time. If this is my only game I get to play why do I have to suffer for 40 minutes while the other team drags out the game. Sure we could come back, but I just wasted my free time for the evening being trolled. Is this game just useless to play if you only have time for 1 game? Don't want to leave my other teammates hanging when they want to keep playing, but I also want to be conscious of the time I need to recharge.