The contract size for platinum futures is 50 troy ounces. Suppose you need 500 troy ounces of platinum and the current futures price is $760 per ounce. How many contracts do you need to purchase? How much will you pay for your platinum? What is your dollar profit if platinum sells for $810 a troy ounce when the futures contract expires? What if the price is $710 at expiration? (A negative value should be indicated by a minus sign. Do not round intermediate calculations. Round your answers to the nearest whole number.)