The probability that an accounting company will make 0, 1, 2, or 3 errors in preparing a yearly budget for a small company is 0.50, 0.28, 0.15, and 0.07 respectively. If 20 companies have the firm prepare their budgets, find the probability that 9 will contain 0 errors, 6 will contain one error, 3 will contain 2 errors, and 2 will contain 3 errors.