Suppose that Charles is given a set of tasks to complete at his job every day. If he finishes them early, he receives a $20 bonus. If he finishes them on time, he receives a $10 bonus. If he does not finish them, he receives no bonus. Charles finds there is a 30% chance on any given day that he will finish the tasks early, a 50% chance that he will finish on time, and a 20% chance that he will not finish. The expected value of his bonus on any given day is ____ dollars