Of course this works, why wouldn't it? If they are motivated, they will do something.
This is not the type of motivation that they should be learning though, tell them WHY they should learn (much more specific then they do now) and maybe something will happen. School shells out enough money to pay for their education, better use for this money would be to pay for college for those who want it.
I can tell you that paying kids to do this will diminish the intrest of those who would do it anyways. It turns this into a job and kids don't need a job yet. Kids who do this for the money will give you what you ask for (as a rule) and nothing more.
I very much belive there are better ways to fix the education system, and the first thing to do is motivate the kids; not with money, but with a knowledge of why they are there, why they should try hard, and give them an intrest in learning. That is what will be best for the kids and for the country, not bribing them with money, that will just cause them to expect money for everything.