Lihaan walks 8 m towards South from his office to reach a park. He then turns…
2024
Lihaan walks 8 m towards South from his office to reach a park. He then turns left and walks 15 m to reach a traffic signal. From there, he turns 90° anticlockwise and walks 8 m to reach a coffee shop. From the coffee shop, he turns left and walks 8 m to reach home. What is the horizontal distance between Lihaan's office and the coffee shop, and in which direction is the coffee shop from Lihaan's office?
- A.
15m, East
- B.
15 m, West
- C.
12m, East
- D.
12m, West
Show answer & explanation
Correct answer: A
Concept: In a direction-sense problem, track the walker's net displacement along two perpendicular axes (North-South and East-West). A left turn rotates the current facing direction 90° anticlockwise and a right turn rotates it 90° clockwise; a stated "90° anticlockwise" turn behaves exactly like a left turn. Two straight-line legs walked in exactly opposite directions cancel each other out, so only the leg(s) along the axis that does not cancel decide the final direction and distance.
Application -- tracing each leg from the office:
Office to park: facing South, walks 8 m South.
Park to traffic signal: at the park he turns left. A left turn while facing South changes the facing to East, so he walks 15 m East to the traffic signal.
Traffic signal to coffee shop: he turns 90° anticlockwise -- the same rotation as a left turn -- so the facing changes from East to North, and he walks 8 m North to the coffee shop.
Netting the two vertical (South-North) legs: the 8 m walked South (office to park) and the 8 m walked North (traffic signal to coffee shop) are equal and opposite, so they cancel completely -- the coffee shop lies on the same horizontal line as the office.
With the vertical component cancelled, the only surviving displacement is the 15 m Eastward leg from the park to the traffic signal, so the coffee shop is 15 m East of the office.
Cross-check: the diagram below places the office and the coffee shop on the same top edge of a rectangle, 15 m apart, with the park and the traffic signal directly below them on the bottom edge -- confirming the office and coffee shop differ only in the East-West direction, by exactly 15 m. (The final leg to home, from the coffee shop, describes a point beyond this question and does not affect the office-to-coffee-shop distance being asked.)

Therefore, the coffee shop is 15 m East of Lihaan's office.