Afurniture manufacturer produces chairs and sofas. the chairs require 20 feet of wood, 1 lb. of foam rubber, and 2 square yards of material. the sofas require 100 feet of wood, 50 ibs. of foam rubber, and 20 square yards of material. the manufacturer has in stock 1900 feet of wood, 500 ibs. of foam rubber, and 240 square yards of material. if the chairs can be sold for $20 each and the sofas for $300 each, how many of each should be produced to maximize the income?