20. You don't have to show your work. Just the answer is enough

Barbara is a research biologist for Green Carpet Lawns. She is studying the effects of fertilizer type, temperature at time of application, and water treatment after application. She has three fertilizer types, five temperature zones, and five water treatments to test. Determine the number of different lawn plots she needs in order to test each fertilizer type, temperature range, and water treatment configuration. 13 0 3 O 26 O 75