In the following figure small square represents the persons who know English,…

Concept: In a Venn diagram built from overlapping shapes, each enclosed region stands for exactly the people who belong to every shape whose boundary encloses that region, and to none of the shapes whose boundary excludes it. To find how many people belong to a specific combination of categories, locate the single region that lies inside all of the required shapes and outside every shape not required.

Application: Here, the small square marks English, the circle marks Hindi, and the big square marks Telugu, while the triangle marks Marathi. The question needs persons in English, Hindi, and Telugu only, so the target region must lie inside the small square, the circle, and the big square together, and outside the triangle. In the figure, the region satisfying all three conditions is labelled 2.

• Region 7 lies inside the triangle, the circle, and the big square — that is Marathi, Hindi, and Telugu, not the English-Hindi-Telugu combination the question asks for.

• Region 8 lies inside the circle and the big square only — that is Hindi and Telugu, but it sits outside the small square, so it leaves out English.

• Region 12 lies inside the small square alone — English only, with no overlap with Hindi or Telugu at all.

Cross-check: Region 2 is the only region enclosed simultaneously by the small square (English), the circle (Hindi), and the big square (Telugu), while staying outside the triangle (Marathi) — so 2 persons can speak all three of English, Hindi, and Telugu.