Algebra-22 (Sets) (NASSCOM- Sample Problems)

In a class, 30 students pass in English, and 20 students in Math, while some students among these pass in both. How many more students do only English, as compared to those doing only Math?

(1)10      (2)15         (3)20   (4) Indeterminate

Solution follows here:

Solution:
It’s a simple set theory problem.

Number of students passed in English = n(E) = 30

Number of students passed in Math = n(M) = 20

Let number of students passed in both = n(E∩M) = x;

Number of students passed in only English = n(E)- n(E∩M) = 30-x        ------(1)

Number of students passed in only Math = n(M)- n(E∩M) = 20-x         ------(2)

Difference between (1) and (2) gives then number of students do only English, as compared to those doing only Math.

(30-x)-(20-x) = 10

Answer (1)