A factory produces two types of items, A and B. Each item of type A weighs $x$ kilograms, and each item of type B weighs $y$ kilograms. A shipment containing 50 items of type A and 30 items of type B has a total weight of 1600 kg. Another shipment containing 70 items of type A and 40 items of type B has a total weight of 2200 kg. Which system of equations can be used to determine the values of $x$ and $y$?