Pranoy is at a pet store and sees three turtle tanks. Each tank holds a different volume (in Liters) of water and a different number of turtles. Tank A holds 108 L and 15 turtles. Tank B holds 84 L and 12 turtles. Tank C holds 156 L and 20 turtles. Order the tanks by volume per turtle from least to greatest. Set up equivalent ratios for each tank.