Answer:
KORBIN COMPANY
Common Size Comparative Income Statements
For Years Ended December 31, 2017, 2016, and 2015
                                           2017       %          2016          %      2015          %
Sales                            $ 555,000  100    $340,000   100   $278,000  100
Cost of goods sold         283,500    51.1     212,500    62.5   153,900    55.4
Gross profit                      271,500   48.9    127,500     37.5    124,100    44.6
Selling expenses            102,900    18.5      46,920     13.8     50,800     18.3
Administrative expenses 50,668     9.1      29,920       8.8     22,800      6.0
Total expenses               153,568   27.7      76,840     22.6     73,600    26.5
Income before taxes       117,932   21.2      50,660      14.9    50,500      18.2
Income taxes                   40,800     7.4       10,370        3.1      15,670       5.6
Net income                    $ 77,132    13.9   $40,290       11.9  $34,830      12.5
Explanation:
a) Data and Calculations:
KORBIN COMPANY
Common Size Comparative Income Statements
For Years Ended December 31, 2017, 2016, and 2015
                                           2017       %          2016          %      2015          %
Sales                            $ 555,000  100    $340,000   100   $278,000  100
Cost of goods sold         283,500    51.1     212,500    62.5   153,900    55.4
Gross profit                      271,500   48.9    127,500     37.5    124,100    44.6
Selling expenses            102,900    18.5      46,920     13.8     50,800     18.3
Administrative expenses 50,668     9.1      29,920       8.8     22,800      6.0
Total expenses               153,568   27.7      76,840     22.6     73,600    26.5
Income before taxes       117,932   21.2      50,660      14.9    50,500      18.2
Income taxes                   40,800     7.4       10,370        3.1      15,670       5.6
Net income                    $ 77,132    13.9   $40,290       11.9  $34,830      12.5
KORBIN COMPANY
Comparative Balance Sheets
December 31, 2017, 2016, and 2015
                                                   2017            2016         2015
Assets
Current assets                       $ 52,390     $37,924      $51,748
Long-term investments                      0            500         3,950
Plant assets, net                      100,000      96,000       60,000
Total assets                           $152,390   $134,424    $115,698
Liabilities and Equity
Current liabilities                    $22,800     $19,960    $20,300
Common stock                         72,000       72,000      60,000
Other paid-in capital                  9,000         9,000         6,000
Retained earnings                   48,590       33,464       29,398
Total liabilities and equity   $152,390    $134,424    $115,698
b) Korbin's common size income statement shows each line item expressed as a percentage of the revenue or sales value.  This analysis of individual financial statement items is also known as a vertical analysis of the financial statement, making line items comparison to a common base easy.