Well, some I spend more time on than others. The one with the stripy green background didn't take me very long. It was a part of a series for my art class. I did that one at the same time as two others. The rest of them took 1-2 weeks individually. The last one, the red and white one, took me a good 3 weeks. That's the one I sold.
Oh, and I've also tried to draw some fitness related stuff. I haven't taken a figure drawing class, but I have drawn some pictures of muscular bodies. I'm thinking of taking a figure drawing class sometime in the future. I've mastered the car body, and it's time to learn how to paint a human body.