If the store can only buy them in bulks of ten, then you take your number of desired cars (3,000) and divide it by the bulk amount (10) and it will give you your amount of bulk you need to buy to fulfill your desired amount of product (300). Simplified, you take your cars that they want, divide it by how many come in a set, and the answer will be how many sets they need to order. You need to use both the amount of desired cars and number of cars in a set as you primary information to solve this problem. Hope this helped!
