Hose R can fill an empty pool in 4/5 the time that hose S can empty a full pool. If they are both used at the same time with an empty pool, the pool will be filled in 20 hours. What is the rate of each?

Hello people, i have a math question that i need with, me, i will give the correct one brainiest, and for the other correct people, a and 5 stars.

What is the difference between regular convex and concave polygons

Mrs. morton has a special reward system for her class. when all her students behave well, she rewards them by putting 3 marbles into a marble jar. when the jar has 100 or more marbles, the students have a party. right now, the the jar has 24 marbles. how could mrs. morton reward the class in order for the students to have a party?