Luna's Electronics purchased TV's from the manufacturer for $600 each less discounts of 20% and 10%. The regular markup on TV's is 40% of the regular selling price, and Luna's expenses are 15% of the regular selling price. On the Boxing day sale, the sales price was reduced to $482.40. (a) What was tuna's cost for each TV? (b) What was the regular selling price? (c) What was the rate of markdown for the sale