You get 10 points + 1 point for each second left on the clock when you answer. So, if you answer a question after just 6 seconds, then you'll get 14 points. That's 10 points + 4 points for each second left on the clock (10 - 6 seconds = 4).
If you get a question wrong, then you get 5 points knocked off. So, use the Pass button wisely! :)