Give the step-by-step reasoning process and then the final answer. It takes 320 rose petals to make an ounce of perfume. If each rose produces 8 petals, and there are 12 roses per bush, how many bushes will Fern have to harvest to make 20 12-ounce bottles of perfume?
First find the number of roses needed for one ounce of perfume: 320 petals / 8 petals / rose = 40 roses. Then multiply the number of roses needed for one ounce by the number of ounces per bottle to find the number of roses per bottle: 40 roses / ounce * 12 ounces / bottle = 480 roses / bottle. Then multiply that number by the number of bottles to find the total number of roses needed: 480 roses / bottle * 20 bottles = 9600 roses. Then divide that number by the number of roses per bush to find the number of bushes Fern needs to harvest: 9600 roses / 12 roses / bush = 800 bushes.
The final answer: 800.