Singapore's time is 8 hours ahead of GMT (GMT +8); noon in greenwich would equate to 8pm in Singapore.
12 noon
1700 GMT is 11:00 AM Central Time. Central Time is 6 hours behind GMT, so you would subtract 6 hours from 17:00 GMT to get the local time in Central Time.
1 hour
time ball
AM = Ante Meridiem (Latin for "before noon") PM = Post Meridiem (Latin for "after noon") GMT = Greenwich Mean Time, the standard time in London at 0° longitude
17:00 GMT is 11:00 AM Central Standard Time (CST) or 12 Noon Central Daylight Time (CDT).
2 hours after noon UTC
The time zone for Japan is GMT + 9 hours.
Japan is in the Japan Standard Time (JST) zone, which is UTC+9. Therefore, during the winter months when Daylight Saving Time is not in effect, the GMT of Japan is UTC+9.
At 12 noon GMT, the time in Madrid is 1 PM during Central European Time (CET), which is typically observed from the last Sunday in October to the last Sunday in March. However, during Central European Summer Time (CEST), which runs from the last Sunday in March to the last Sunday in October, the time in Madrid would be 2 PM. Therefore, the time in Madrid at 12 noon GMT depends on the time of year.
Japan Standard Time (JST) UTC/(GMT) +9