Luigi's Restaurant offers a "buy one dinner get the other dinner for half price" sale. The "half price" refers to the lower-priced dinner. A customer orders a pasta dinner with a regular price of $30.00, and a chicken dinner with a regular price of $17.00 (a) What was the overall markdown value at which the dinners were sold? (b) What was the overall markdown rate at which the dinners were sold? (a) The markdown value is $ (Type an integer or a decimal.)