A store is giving out cards labeled 1 through 10 when customers enter the store. If the card is an even number, you get a 15% discount on your purchase that day. If the card is an odd number greater than 6, you get a 30% discount. Otherwise, you get a 20% discount. The table shows the results of 400 customers. What is the relative frequency for each discount? Use pencil and paper. If the manager of the store wants approximately half of the customers to receive the 20% discount, does this seem like an appropriate method? Explain.