Let A= no. of students passed in the first semester. B= no. of students passed in second semester. Given, n(A)=260,n(B)=210 ∴ n(A)= no. of students did not pass in first semester. =500−260=240 Similarly, n(B)=500−210=290 Thus, we have n(A∪B)=170 n(A)=240,n(B)=290 ∴ n(A∪B)=n(A)+n(B)−n(A∩B) ⇒ 170=240+290−n(A∩B) ⇒ n(A∩B)=360 So, n (students passed in both semester) =500−360=140