Question:

Sakshi starts from her college and walks 12 km towards the North. She then turns right and walks 5 km. After that, she turns right again and walks 4 km. She then turns left and walks 7 km. Finally, she turns left and walks 1 km. How far is Sakshi from her college and in which direction?

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Always verify the final square root before selecting the option. Here, \[ 9^2+12^2=81+144=225 \] and \[ \sqrt{225}=15, \] not 13. Also, \((9,12,15)\) is a multiple of the famous Pythagorean triplet \((3,4,5)\). Hence, the correct option is (D) 15 km, North-East.
Updated On: Jun 30, 2026
  • 13 km, North-East
  • 12 km, South-East
  • 10 km, North-West
  • 15 km, North-East
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The Correct Option is D

Solution and Explanation

Concept: In direction problems, calculate the net displacement separately along the North--South and East--West directions.

• Movement towards North is taken as positive and South as negative.

• Movement towards East is taken as positive and West as negative.

• The shortest distance from the starting point is obtained using the Pythagoras Theorem: \[ \text{Distance}=\sqrt{(\text{Vertical Displacement})^2+(\text{Horizontal Displacement})^2}. \]

Step 1: Trace Sakshi's complete movement.
\[ \begin{array}{|c|c|c|} \hline \textbf{Movement} & \textbf{Distance} & \textbf{Direction} \\ \hline 1 & 12\ \text{km} & \text{North} \\ \hline 2 & 5\ \text{km} & \text{East} \\ \hline 3 & 4\ \text{km} & \text{South} \\ \hline 4 & 7\ \text{km} & \text{East} \\ \hline 5 & 1\ \text{km} & \text{North} \\ \hline \end{array} \]

Step 2: Calculate the net displacement in North--South direction.
\[ 12-4+1=9\ \text{km North} \] Hence, \[ \boxed{\text{Net Vertical Displacement}=9\ \text{km North}} \]

Step 3: Calculate the net displacement in East--West direction.
\[ 5+7=12\ \text{km East} \] Hence, \[ \boxed{\text{Net Horizontal Displacement}=12\ \text{km East}} \]

Step 4: Find the shortest distance from the college.
Using Pythagoras Theorem, \[ \begin{aligned} \text{Distance} &=\sqrt{9^2+12^2} \\ &=\sqrt{81+144} \\ &=\sqrt{225} \\ &=15\ \text{km}. \end{aligned} \] Since the final position lies towards the North and the East of the starting point, the direction is

North-East. Therefore, \[ \boxed{\text{Required Answer}=15\ \text{km, North-East}} \]
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