If a news is broadcast from London at 1:45 p.m. on Monday, at what time and on what day it will be heard at Dhaka (90° E)?

The time difference between two locations is determined by their longitudinal distance. The Earth rotates 360° in 24 hours, which equates to 15° per hour [2]. London is located at the Prime Meridian (0°), while Dhaka is at 90° E longitude. To find the time difference, divide the longitude by 15° (90 / 15 = 6 hours). Since Dhaka is east of London, it is ahead in time [1]. Bangladesh Standard Time (BST) is officially 6 hours ahead of Greenwich Mean Time (GMT) [2]. If a news broadcast occurs in London at 1:45 p.m. on Monday, the time in Dhaka is calculated by adding 6 hours to the London time. Adding 6 hours to 1:45 p.m. results in 7:45 p.m. on the same day, Monday. Therefore, the broadcast will be heard in Dhaka at 7:45 p.m. on Monday.

Sources

1. [1] Certificate Physical and Human Geography , GC Leong (Oxford University press 3rd ed.) > Chapter 2: The Earth's Crust > Longitude and Time > p. 12
2. [2] Exploring Society:India and Beyond. Social Science-Class VI . NCERT(Revised ed 2025) > Chapter 1: Locating Places on the Earth > LET'S EXPLORE > p. 21