Sally can paint a room in 3 hours while it takes steve 6 hours to paint the same room how long would it take them to paint the room if they worked together ?

Megan and desmond each add the same amount of water to their aquarium megan makes 5 ml of chemical solution with every gallon of water for her aquarium desmond mixed 8 ml of chemical solution for every 2 gallon of the water for his aquarium.