Ellipse center (0,0) so its eqn is x^2/a^2 + y^2/b^2 = 1 major axis is horizontal n length 18 so at y=0, x=+/-18 a=18 minor axis is vertical n length 2 so at x=0, y=+/-2 b=2
Exactly one activity: 246 None of the activities : 1 At least one activity: 74 Snowboarding and Ice skating but not skiing: 5 Snowboarding or ice skating but not skiing: 132. Only skiing : 119. The diagram is in the attachment.