Give the step-by-step reasoning process and then the final answer. A family just bought a newborn puppy that must eat a special type of dog food until it is 1 year old. The puppy needs to eat 2 ounces of this special dog food per day during the first 60 days of its life. After that, it needs to eat 4 ounces per day of the special food until it is old enough to eat regular dog food. If the special dog food is only sold in 5-pound bags, and there are 16 ounces in a pound, how many bags will the family need to buy to feed the puppy until it is old enough to eat regular dog food?
The puppy will consume 60 * 2 = 120 ounces of the special dog food in the first 60 days. This leaves 365 - 60 = 305 days where the puppy will consume 4 ounces of food per day, or 305 * 4 = 1220 ounces of the special food. Thus, the puppy requires a total of 120 + 1220 = 1340 ounces of food before it is 1 year old. Each 5 - pound bag contains 5 * 16 = 80 ounces of special dog food. Therefore, the puppy will need to eat 1340 / 80 = 16.75 bags of the special dog food, meaning the family will need to buy 17 bags.
The final answer: 17.