if you want to know something, you'll learn to know without beeing paid for staying after hours in the school. Thank G-d that is just a trial..but who knows whats next!
Jasmina, you can't learn anything without studying it after school (if one needs that kind of help.) The money isn't necessary, although I don't frown on other forms of positive reinforcement.... verbal encouragement, a happy face sticker, a pencil or pen, or even goodie bags filled with learning materials (reading books, crayons or notebooks).