Determine the missing amounts.

$\backslash$table$[[,\backslash$table$[[$Unit Selling$],[$Price$]],,,\backslash$table$[[$Unit Variable$],[$Costs$]],,\backslash$table$[[$Unit Contribution$],[$Margin$]],\backslash$table$[[$Contribution$],[$Margin Ratio$]],],[1.,$$$600,,,$$$300,$$$,($a$)1,,\%($b$)],[2.,$$$250,,$$$,,($c$),$$$70,,\%($d$)],[3.,$$$,($e$),$$$,,($f$),$$$750,30,\%$