We are given in the question that:
We are meant to calculate the number of gallons that will fill the entire bin, such that we can have:
We know that the ratio of both expressions will give the same value, therefore, the equation that can be used to solve will be:
We can further solve to get the amount of water by cross-multiplying:
Solving, we have:
Therefore, it will take 3/8 gallons to fill the bin.