10 Balls in 5 Lines | Puzzles for Interview - Interview Preparation PDF Download

Problem Statement

You are given ten balls, and your goal is to arrange these ten balls into five lines in such a way that each line contains exactly four balls. The challenge lies in finding a configuration where all ten balls are used, and each line has the required number of balls.

Solution

To solve this puzzle, we need to think creatively and consider three-dimensional arrangements as well. The solution can be visualized as a tetrahedron, which is a pyramid with a triangular base.

1. First, arrange three balls in an equilateral triangle on a flat surface. This forms the base of our tetrahedron.
2. Next, place another ball in the center of the triangle, resting on the flat surface. This ball is now part of three new lines that connect it to each corner of the triangle.
3. Finally, place the tenth ball on top of the center ball, suspending it above the base. This top ball forms another three lines, connecting it to each of the three balls forming the triangle base.

This arrangement forms a total of five lines, each containing four balls. The lines are as follows:

• The three lines along the triangle base, with the center ball included.
• The three lines connecting the top ball to the three balls forming the triangle base.

Conclusion

The 10 Balls in 5 Lines puzzle can be solved by thinking beyond two-dimensional arrangements and considering a three-dimensional solution. By arranging the balls into a tetrahedron shape, we can successfully create five lines, each containing exactly four balls. This puzzle demonstrates the importance of creative thinking and looking at problems from different perspectives.