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UPSC Prelims 1992 · World Geography · Earth in Space
If Amsterdam is X + 1, Montreal is X - 5, Tokyo is X + 9 and Lisbon is X, X denotes
- (a) GMT
- (b) The temperature as measured by the Kelvin scale to arrive at the temperature as measured by the Celsius scale
- (c) Base from which height and depth from the sea-level is measured
- (d) The figure to be used for converting the Imperial System to the Metric System
Show the answer and explanation
Answer: (a) GMT
Lisbon is on GMT; Amsterdam +1, Montreal −5, Tokyo +9 — X = GMT.
The idea
A set of city values written as X plus or minus hours describes a common time reference. Positive offsets mean clocks ahead of that reference; negative offsets mean clocks behind it. Identify the shared baseline rather than treating each city as a separate conversion.
Also know
The listed offsets should be read as standard-time values in the 1992 question, not as guaranteed clock differences throughout the year. Daylight-saving rules can change some cities’ offsets seasonally. IST stays at UTC + 5:30, while Tokyo uses UTC + 9.
🔒 Tokyo GMT+9, Montreal GMT−5, India GMT+5:30.
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