A sports store had 60 backpacks in stock, some with wheels and some without wheels, before a new shipment of backpacks arrived. The number of wheeled backpacks in the new shipment was twice the number of wheeled backpacks already in stock, and the number of backpacks without wheels in the new shipment was five times the number of backpacks without wheels already in stock. After the new shipment arrived, there
were 330 backpacks in the store. Before the new shipment, there were x wheeled backpacks and y
backpacks without wheels. Which of the following equations can be used with x + y = 60 to solve for x and y?
a. 2x+5y=330
b. 2x+5y=270
c. 5x+2y=270
d. 5x+2y=330