Halal meat market makes up a combination package of beef and pork for meat loaf. The beef is 75% lean (75% beef, 25% fat) and costs the market $0.70 per pound. The pork is 60% lean (60% beef, 40 % fat) and costs the market $0.50 per pound. If the meat loaf is to be at least 70% lean, how much beef and pork should be mixed to keep cost at a minimum?