Final answer:
To calculate the number of respondents who preferred to watch either football or soccer, add the number of respondents who preferred football to the number of respondents who preferred soccer.
Step-by-step explanation:
To calculate the number of respondents who preferred to watch either football or soccer, we need to add the number of respondents who preferred football to the number of respondents who preferred soccer.
From the graph, we can see that 35 respondents preferred football and 20 respondents preferred soccer. Therefore, the total number of respondents who preferred either football or soccer is 35 + 20 = 55.