Of the students at a certain high school, 90 percent took a course in algebra or geometry and 30 percent took courses in both. If the percent of students who took a course in algebra was 2 times the percent of students who took a course in geometry, what percent of the students took a course in algebra but not geometry?
Select the correct option:
A) 50%	B) 40%	C) 45%	D) 35%	E) 30%
You can also just use the formula   n(A or B) = n(A) + n(B) - n(A and B)   90 = 2X + X - 30   X = 40   2X = 80   This is the number of people who took algebra including those who took both. To get the number of people who took only algebra, 80 - 30 = 50%   50%nswer (50%)
<result>A</result>
Of the students at a certain high school, 90 percent took a course in algebra or geometry and 30 percent took courses in both. If the percent of students who took a course in algebra was 2 times the percent of students who took a course in geometry, what percent of the students took a course in algebra but not geometry?