Heard on the Streets (1)

I. Purely Quantitative & Logic Questions

1. Concentration Problem

You are given two glass jugs. Each contains the same volume, $V$, of liquid. One jug contains pure alcohol, and the other jug contains pure water. A modest quantity, $Q$, of water is poured from the water jug into the alcohol jug, which is then thoroughly mixed. The same modest quantity, $Q$, of (now diluted) alcohol is then poured back into the water jug to equalize the volumes of the jugs at their initial levels.

The initial concentration of alcohol in the alcohol jug equals the initial concentration of water in the water jug (at $100\%$). What is the relationship between the final concentrations of alcohol in the alcohol jug and water in the water jug?