What was the total amount of revenue that a theater received from the sale of 400 tickets, some of which were sold at x percent of full price and the rest of which were sold at full price?
За якую суму фірма набыла кожны з пакетаў акцый, калі пры продажы першага пакета прыбытак склаў 40%, а пры продажы другога — 20%?