What's a real-world problem that can be modeled by the equation 1.25 = 0.75x + 50 ?

Well, you could say that you want to buy something for $1.25. Like a game or a toy or something! So you need to have $1.25 in order to get this item. You have $50 in your savings account you make 0.75 an hour. And then x would represent the number of hours you have to work. It doesn't really make sense since if you have 50$ in your savings account then you would be able to buy it automatically but, for the sake of this let's just pretend! I'm pretty sure this example will work! Hope it helped! 

Jim has run 5/6 of a mile so far. i hope that answers your question! good luck : )