Rohit walks 30 m straight from his school towards the North, Then he turns left and walks 20 m. He turns left again and walks 10 m. Finally, he turns left and walks 20 m to reach point A. What is the shortest distance between his school and point A.

20 m

The correct answer is Option (2) → 20 m

1. Step-by-Step Movement Analysis

Let's assume the School is at the starting coordinates (0, 0).

• Move 1 (North): Rohit walks 30 m North.
• New position: (0, 30)
• Move 2 (Left): Turning left from North means moving West. He walks 20 m.
• New position: (-20, 30)
• Move 3 (Left again): Turning left from West means moving South. He walks 10 m.
• New position: (-20, 20) (since $30 - 10 = 20$)
• Move 4 (Final Left): Turning left from South means moving East. He walks 20 m.
• New position: (0, 20) (since $-20 + 20 = 0$)

2. Final Position (Point A)

Point A is located at coordinates (0, 20).

3. Calculate the Shortest Distance

The shortest distance between the starting point (School) at (0, 0) and the final point (A) at (0, 20) is the straight line connecting them.

• Since the x-coordinates are both 0, the distance is simply the difference in the y-coordinates:

$\text{Distance} = 20 - 0 = \mathbf{20\text{ m}}$