The number of students who took part in the survey is 320 .
25 more 18-year Olds spent between 25 - 35 minutes on social media more than 12-year olds.
From the line graph :
For 18 year old students :
Total number who took part in survey : (0 + 30 + 20 + 60 + 70 + 40 + 60 + 40 + 0) = 320 students
B.)
25 - 35 minutes on social media
For 12 years old :
For 18 years old :
Difference = 165 - 120 = 45
Hence, 25 more 18-year Olds spent between 25 - 35 minutes on social media more than 12-year olds.