Walking across campus, a student interviewed a group of students. 25% of the students took a finance class last semester, 55% took a marketing class last semester, and 40% took neither a finance nor a marketing class last semester. What percent of the students in the group took both a finance and a marketing class?  Choose the correct answer.
A) 60%  B) 50%  C) 25%  D) 20%  E) 10%
{Total} = {finance} + {marketing} - {both} + {neither}   100 = 25 + 55 - {both} + 40   {both} = 20%.   Answer: 20%.
<result>D</result>
Walking across campus, a student interviewed a group of students. 25% of the students took a finance class last semester, 55% took a marketing class last semester, and 40% took neither a finance nor a marketing class last semester. What percent of the students in the group took both a finance and a marketing class?