Systems of Linear Inequalaties

I hate math. Lately, we've been talking about graphing systems of linear inequalities. I wanna know when I'll ever use that in the real-world! (And I don't want any of my smart-*** friends to chime in and tell me, so don't bother.) Hmmm...I think I'll go ride my bike with the wind to my back, but later, I'll ride into the wind, and I want to know exactly how fast I would've been going had there been no wind, and I also wanna know the exact wind speed. Oh wait, no I don't, because I'm in high school, and I don't care about any of that.