Solution Concentration — Definition & Overview

Molality is a less common measurement of concentration, expressed in mol solute / kg total solution and abbreviated as m. If Alex drinks 200 0.5 L cold brew coffees, each with a molarity of 0.1 M, and has a total body mass of 80 kg (after drinking the coffee), what would the approximate molality of coffee solids in his body be? For the sake of this problem, you can approximate his body as being essentially a solution with the mass of his body.