Anewspaper surveyed 1,000 college students to explore trends in time spent studying and time spent playing video games. the survey results are shown in the venn diagram above. “video games” represents students who said they spend more than 1 hour every day playing video games. “studying” represents students who said they spend more than 1 hour every day studying.

Total number of students = 1000, broken down as follow:

324 :   students who said they spend more than 1 hour every day "video games"

368 :   students who said they spend more than 1 hour every day "studying"
  87 :   students who said they spend more than 1 hour in playing & studying 

and 221 students who are neither playing nor studying:

324 + 368 +87 + 221 =  1,000

87 only were playing and studying ,  or 87/1000 = 0.087