CDS Model Paper 3 Mathematics

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