Question

When there is noon at IST meridian, people in another place of the Earth are taking their 6 O' clock morning tea. The longitude of the place is ______.

• A. $7^o{30}^{\prime \prime }E$
• B. $7^o{30}^{\prime \prime }W$
• C. ${172}^o{30}^{\prime \prime }E$
• D. ${90}^{o}W$

Answer 1

Answer: (B)

$7^o{30}^{\prime \prime }W$

If the time of the concerned place is 6 hours behind Indian Standard Time (IST), which itself is 5.5 hours ahead of Greenwich Mean Time (GMT), it means that it is located to the west of Prime Meridian, i.e. 0 degrees meridian. A difference of 15 degrees in longitude represents 1 hour of difference. This means that the given location is located 7.5 (15 divided by 2) degrees west of the Prime Meridian, i.e 7 degrees and 30 minutes W.