A clerk in a bookstore has 90 minutes at the end of each workday to process orders received by mail or on voicemail the store has found in a typical mail order brings in a profit of $30 and a typical voicemail order brings in a profit of $40 each mail order takes 10 minutes to process and each voicemail order takes 15 minutes how many of each type of order should the clerk process how if at all do the maximum profit in optimal processing policy change if the clerk must process at least three email orders and to voicemail orders