UPSC Prelims 2020 · CSAT
Question 31: Logical Reasoning and Mental Ability
A man walks down the backside of his house straight 25 metres, then turns to the right and walks 50 metres again; then he turns towards left and again walks 25 metres. If his house faces to the East, what is his direction from the starting point?
AnswerUPSC’s answer is (d).
The house faces east, so its back is to the west. He walks 25 m west. Turning right while facing west points him north, and he walks 50 m north. Turning left while facing north points him west again, and he walks 25 m west. In total he is 50 m west and 50 m north of the start, which is north-west.
Why each option is right or wrong
- (a) South-east would need him to move east and south; he moved west and north.
- (b) South-west needs a southward move; his only sideways turn took him north.
- (c) North-east needs an eastward move; both westward legs took him away from east.
- (d) Right: 50 m west and 50 m north puts him north-west of the start.
Answer: UPSC’s key. Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2020, General Studies Paper II (CSAT), Series A. The paper on upsc.gov.in.