RRB Group D · Bite-size lessons

Venn Diagram

About 6 min · General Intelligence and Reasoning · English

Time worked out from the lesson's 429 words at 150 words a minute, plus a minute for each question.

Venn diagrams are visual representations of relationships between sets using overlapping circles or closed curves.

Key ideas

• Set: A collection of distinct objects or elements. In Venn diagrams, each set is represented by a circle or closed curve, with the set name typically labeling the circle.
• Universal Set: The rectangle enclosing all circles represents the universal set—the complete collection of all elements under consideration. Elements outside all circles but inside the rectangle belong to none of the named sets.
• Disjoint Sets: Two or more sets with no common elements are shown as non-overlapping circles (e.g., "Males" and "Females" are disjoint—no person can be both).
• Intersection: The overlapping region where two or more sets share common elements. For sets A and B, this region contains elements that are both A AND B (e.g., people who are both "Doctors" and "Women").
• Subset Relation: When all elements of one set are contained within another, the smaller circle is drawn completely inside the larger one (e.g., "Roses" is a subset of "Flowers"—all roses are flowers, but not all flowers are roses).

Watch out for

• Forgetting the subset rule: Drawing "Dogs" and "Animals" as overlapping instead of Dogs completely inside Animals. Fix: If ALL of one category belongs to another, use complete inclusion, not partial overlap.
• Double-counting intersections: Adding A + B directly when they overlap leads to counting shared elements twice. Fix: Always subtract the intersection: A + B - (A∩B).
• Misidentifying disjoint sets: Showing overlap between "Prime numbers" and "Even numbers" beyond the number 2. Fix: Check if there's ANY possible common element; if there is even one (Prime and Even numbers share 2), the circles must overlap; only if there is none are the sets disjoint.

Quick reference

• Disjoint sets: Separate circles (Males/Females, Living/Non-living).
• Subset: Small circle inside large (Roses ⊂ Flowers, Gold ⊂ Metals).
• Overlap formula (2 sets): Total = A + B - Intersection.
• Overlap formula (3 sets): Total = A + B + C - (sum of pairs) + (all three).
• "Some" keyword: Draw overlapping circles with shared region.

Check yourself: 3 questions

This lesson is cut from the topic's note, not rewritten. Fact-checked on 21 Oct 2026: an AI-assisted check of this note against cited sources; the errors it found were corrected that day. Some errors may remain. The questions are from Shishya's validated question bank.

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