UPSC Prelims 2021·CSAT·Logical Reasoning·Arrangement and Puzzles

A bank employee drives 10 km towards South from her house and turns to her left and drives another 20 km. She again turns left and drives 40 km, then she turns to her right and drives for another 5 km. She again turns to her right and drives another 30 km to reach her bank where she works. What is the shortest distance between her bank and her house?

Dalvoy logo
Reviewed by Dalvoy
UPSC Civil Services preparation
Last updated 8 Jul 2026, 4:39 pm IST
  1. A20 km
  2. B25 kmCorrect
  3. C30 km
  4. D35 km

Explanation

The employee's path can be tracked using coordinates, starting her house at (0,0).

  1. Drives 10 km South: Position (0, -10).
  2. Turns left (East) and drives 20 km: Position (20, -10).
  3. Turns left (North) and drives 40 km: Position (20, -10 + 40) = (20, 30).
  4. Turns right (East) and drives 5 km: Position (20 + 5, 30) = (25, 30).
  5. Turns right (South) and drives 30 km: Position (25, 30 - 30) = (25, 0). This is the bank's location.

The house is at (0,0) and the bank is at (25,0). The shortest distance between these two points is the straight-line distance, which is 25 km.

A) 20 km: Incorrect. This would be the net eastward distance before the last two turns. B) 25 km: Correct. This is the calculated shortest distance between the house (0,0) and the bank (25,0). C) 30 km: Incorrect. This is the net northward distance before the last two turns, or the distance of the last leg. D) 35 km: Incorrect. This value does not correspond to any significant part of the journey or the final distance.

The final answer is B) 25 km.

Logical Reasoning: A bank employee drives 10 km towards South from her house and turns to her left and drives another 20 km. She again turn
ShareWhatsAppXTelegram

Related questions

More UPSC Prelims practice from the same subject and topic.