Q.3 In an engineering college of 10,000 students, 1,500 like neither their core branches
nor other branches. The number of students who like their core branches is 1/4th of
the number of students who like other branches. The number of students who like
both their core and other branches is 500.
The number of students who like their core branches is
(A) 1,800
(B) 3,500
(C) 1,600
(D) 1,500
The number of students who like their core branches is 1,800.
This GATE CSE 2024 Set 2 question tests Venn diagram concepts for two sets: core branches (C) and other branches (O). Use set theory to solve it step-by-step.
Key Data
- Total students (U) = 10,000
- Students liking neither = 1,500, so |C ∪ O| = 10,000 – 1,500 = 8,500
- |C ∩ O| = 500 (both)
- |C| = (1/4) |O|
Solution Steps
- Apply the union formula: |C ∪ O| = |C| + |O| – |C ∩ O|
- Substitute: 8,500 = (1/4)|O| + |O| – 500
- Simplify: 8,500 + 500 = (5/4)|O|
- 9,000 = (5/4)|O|
- |O| = 9,000 × (4/5) = 7,200
- |C| = 7,200 / 4 = 1,800
Verification
Only core = 1,800 – 500 = 1,300; only other = 7,200 – 500 = 6,700. Total = 1,300 + 6,700 + 500 + 1,500 = 10,000.
Option Analysis
- (A) 1,800: Matches calculation exactly
- (B) 3,500: Too high; assumes |C| = (1/4) of union or ignores both, yielding incorrect |O| = 14,000
- (C) 1,600: Underestimates; possibly from 8,500 – 500 – 3,400 error in ratios
- (D) 1,500: Equals neither; confuses with students liking no branches
In competitive exams like GATE CSE, engineering college 10000 students core branches problems using Venn diagrams test set theory mastery. This 2024 Set 2 question involves 1,500 students liking neither core nor other branches, core likers as 1/4th of other branch likers, and 500 liking both—find core branch likers.
Why Venn Diagrams Matter
Venn diagrams visualize overlaps: core (C), other (O). Neither gives complement; union formula resolves totals. Common trap: confusing total core with only core.
Full Breakdown
As solved above, |C| = 1,800 fits options perfectly. Practice similar for CSIR NET quantitative aptitude.
Keywords: engineering college 10000 students, core branches venn diagram, GATE CSE 2024 set 2, students like neither core nor other branches