Final answer:
To fill the entire bin, she will need 1/10 gallons of water.
Step-by-step explanation:
To find the amount of water that will fill the entire bin, we need to set up an equation using proportions. If 1/5 gallons of water fills 2/3 of the bin, then x gallons of water will fill the entire bin. The equation is (1/5)/(2/3) = x/1. To solve for x, we can cross multiply and get x = (1/5)*(1/2) = 1/10 gallons.