Answer:
73.4%
Step-by-step explanation:
First, find the total number of people:
3605+1306=4911 people
The formula for any probability is:
Part / Whole
3605 respondents out of the total 4911 people say they use a social networking site
3605/4911 = 0.7341
Multiply this by 100 to get a percent
Thus, 73.4%