This is a slightly different type of a mixture problem from Dan Griller.
“Two containers A and B sit on a table, partially filled with water. First, 40% of the water in A is poured into B, which completely fills it. Then 75% of the water in B is poured into A, which completely fills it. 80% of the water in A is poured into B, which completely fills it. Calculate the ratio of the capacity of container A to the capacity of container B, and the fraction of container A that was occupied by water at the start.”
See the Two Containers Mixing Puzzle for solution.
A simple method for finding the ratio of capacities.
75% of B is transferred to A to make A full.
To make B full again, same quantity should be transferred from A to B. This is equivalent to 80% of A.
Thus 75% of B is same as 80% of A. It implies that, the ratio of the two capacities is
A/B=75/80=15/16