two pools are being drained.To start,the first pool had 3100 liters of water and the second had 3472 liters of water.Water is being drained from the first pool at of 21 liters per minute.water is being drained from the second pool at a rate of 33 liters per minute
First pool: 21 liters per min so to get 3100 gone do 3100 divided by 21 which equals 147 Second pool: 33 liters per min and you have 3472 divided 33 = 105
