Waterway Company's record of transactions concerning part WA$6$ for the month of September was as follows:

$\backslash$table$[[$Purchases$,$Sales$],[$September$,1,($balance on hand$),300,$@$,$$$12\mathrm{.}90,$September,$4,400],[3,,200,$@$,13\mathrm{.}00,,17,600],[$:$,12,,300,$@$,13\mathrm{.}15,,27,300],[16,,300,$@$,13\mathrm{.}20,,30,200],[22,,500,$@$,13\mathrm{.}20,,,],[26,,300,$@$,13\mathrm{.}30,,,]]$