Piazzanos Pizzeria has a buy-1-get-1-free special on triple cheese pizzas, and a buy-2-get-1-free special on meat lovers pizzas. If the standard price for a pizza is $5, how much does it cost, in dollars, to purchase 10 triple cheese and 9 meat lovers pizzas using the special pricing? Let's think first. Chain of thought:
Using buy - 1 - get - 1 - free pricing, it costs 1 * $5 = $5 to buy 2 triple cheese pizzas. At $5 per 2 pizzas, it costs $5 / 2 = $2.5 per triple cheese pizza. Using buy - 2 - get - 1 - free pricing, it costs 2 * $5 = $10 to buy 3 meat lovers pizzas. At $10 per three pizzas, it cost $10 / 3 = $3 and $1 / 3 per meat lovers pizza. With the buy - 1 - get - 1 - free pricing, 10 triple cheese pizzas are 10 * $2.5 = $25. With the buy - 2 - get - 1 - free pricing, 9 meat lovers pizzas are 9 * ($3 + $1 / 3) = $30. In total, for 10 triple cheese and 9 meat lovers pizzas, it will cost $25 + $30 = $55.
Therefore, the answer is 55.