$2-48$ Finding unknown amounts. An auditor for the Internal Revenue Service is trying to reconstruct some partially destroyed records of two taxpayers. For each of the cases in the accompanying list, find the unknowns designated by the letters A and B for Case $1$ and C and D for Case $2.$

$\backslash$table$[[,\backslash$table$[[$Case $1],[($in thousands$)]],],[$Accounts receivable, $12/31,$$$8,000,$$$3,150$