Question

# Browser choices of 95 students in a class are being studied. 45 students use google chrome,...

Browser choices of 95 students in a class are being studied. 45 students use google chrome, 40 students use safari, and 35 students use internet explorer. 15 students use google chrome and safari, 10 students use google chrome and explorer, and 10 students use safari and internet explorer. 5 students use all three browsers. How many students use none of these 3 browsers?

P(A U B U C) = P(A) + P(B) + P(C) - P(A B) - P(B C) - P(A C) + P(A B C)

Number of students using at least one of these browsers = Number of students using google chrome + Number of students using safari + Number of students using internet explorer - Number of students using google chrome and safari - Number of students using google chrome and explorer - Number of students using safari and internet explorer + Number of students using all 3 browsers

= 45 + 40 + 35 - 15 - 10 - 10 + 5

= 90

Number of students using none of these 3 browsers = Total number of students - Number of students using at least one of these three browsers

= 95 - 90

= 5