If a circle has a diameter of 30 meters, which expression gives its area in square meters?

A 15•pie
B. 30²•pie
C. 30•pie
D. 15²•pie

You want to buy a car. you have a choice of six different dealerships. each dealership carries the same two car companies, and sells eight different models that all come in four colors. if you must choose one option from each of these four categories, how many different cars can you buy if you want a black or blue hyundai?