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

In a multi-shape Venn diagram, the count written inside a region tells the number of people belonging to every category whose shape encloses that region and no other. So the region enclosed only within one shape's boundary, untouched by any other shape, gives the count of persons who belong exclusively to that one category.

1. The figure's legend assigns the small square to English speakers, the triangle to Marathi speakers, the big outer square to Telugu speakers, and the circle to Hindi speakers.

2. The diagram itself marks, with an arrow, the specific region of the small square meant for English speakers, so first locate that exact region.

3. That region lies inside the boundary of the small square only. It does not fall inside the triangle, the circle, or the big square, so its count represents persons who know only English.

4. Read the value written in that exclusive region: 12.

Every other value that touches the small square's boundary also falls inside the circle, so those persons know Hindi as well and cannot be counted as knowing only English. Only the region marked 12 satisfies the only-English condition.

Hence, 12 persons can speak only English.