Bunuel wrote:

How many attendees are at a convention if 150 of the attendees are neither female nor students, one-sixth of the attendees are female students, two-thirds of the attendees are female, and one-third of the attendees are students?

A. 300

B. 450

C. 600

D. 800

E. 900

We will use the overlapping sets formula, which is:

#(attendees) = #(female) + #(student) - #(both female and student) + #(neither female nor student).

Let’s denote the total number of attendees by x, i.e., #(attendees) = x.

Since 150 of the attendees are neither female nor student, #(neither female nor student) = 150.

Since 1/6 of the attendees are female students, #(both female and student) = (1/6)x.

Since 2/3 of the attendees are female, #(female) = (2/3)x.

Since 1/3 of the attendees are students, #(students) = (1/3)x.

Let’s plug in each of the above into the formula:

x = (2/3)x + (1/3)x - (1/6)x + 150

x = x - (1/6)x + 150

(1/6)x = 150

x = 900

Answer: E

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