if you buy 50 bales of hay at $3.56 each, and then buy an additional 234 bales at $3.33 each, how much do you pay for the entire lot of 284 bales?
Since cost = price * quantity, we have:
Total lot cost = price(1) of hay * bales(1) of hay + price(2) of hay * bales(2) of hay
Total lot cost = 3.56...