We will use the virtual currency chapaa (sheng for cash) to symbolize the fact that it can be redeemed for a real world item in this case airtime.
Inviting friends: if your friend accepts, you both receive (2 chapaa)
Successfully completing a simulation will award you 20CP
Successfully completing a question will award you 5CP
Achieving 10 correctly answered questions in a row will give you 5CP bonus points.