= Solution
For a convex droplet, the <Kelvin equation> gives $\ln(p_{\rm eq}(r)/p_{\rm sat})=2\gamma\overline V_l/(rRT)$. Smaller droplets therefore require a higher equilibrium <vapor pressure>. At a common ambient <vapor pressure>, sufficiently small droplets evaporate while larger ones can grow, transferring material through the <vapor>. \b[<Ostwald ripening> decreases the droplet count and increases a characteristic surviving radius.] Direct collision and coalescence can also reduce the count but are a distinct mechanism. In a closed container the final state depends on total <liquid>/<vapor> inventory and volume; an initially undersaturated, liquid-poor system can lose all droplets rather than indefinitely grow a large one.
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