Answer:
Time Warner, Inc.
a. 
                                      Turner      Home Box Office  Warner Bros.   Total
Segment Revenues
(in millions)                  $21,700            $22,200         $80,600      $124,500
Variable costs                 4,774                10,434           25,792           41,000
Contribution margin  $16,926               $11,766        $54,808        $83,500
Contribution ratio     78% (100 - 22)    53% (100 -47) 68% (100 -32)   67%
b. Certainly, Turnover and Warner Bros. are more profitable businesses than Home Box Office in terms of total contribution margin (dollars) and contribution margin ratio.
Explanation:
a) Data and Calculations:
Segment Revenues
(in millions)
Turner (cable networks and digital media) $21,700
Home Box Office (pay television) 22,200
Warner Bros. (films, television, and videos) 80,600
Assume that the variable costs as a percent of sales for each segment are as follows:
Turner 22%
Home Box Office 47%
Warner Bros. 32%
 
b) The contribution margin ratio for the three segments can easily be determined by subtracting the variable costs percentages from 100 for each segment instead of doing more computations (Contribution margin/Sales Revenue * 100).  But the results are the same for either method.