If the time of a place located on 165° E meridian is 11 : 00 p. m. on Sunday, what would be the time at the place located on 165° W meridian ?

To determine the time at 165° W, we calculate the longitudinal difference from 165° E. Moving westward from 165° E to the Prime Meridian (0°) covers 165°, and from 0° to 165° W covers another 165°, totaling 330°. Since the Earth rotates 15° per hour, 330° corresponds to a 22-hour time difference (330/15 = 22). Moving westward implies subtracting time [1]. Subtracting 22 hours from 11:00 p.m. Sunday results in 1:00 a.m. Sunday. Alternatively, crossing the International Date Line (180°) eastward from 165° E to 165° W involves a 30° difference (2 hours). Crossing the IDL from west to east (towards the Americas) requires subtracting a day, but since we are only 2 hours apart across the line, 11:00 p.m. Sunday minus 22 hours (or adding 2 hours and subtracting a day) yields 1:00 a.m. Sunday [2].

Sources

1. [1] Exploring Society:India and Beyond. Social Science-Class VI . NCERT(Revised ed 2025) > Chapter 1: Locating Places on the Earth > Understanding Time Zones > p. 20
2. [2] Certificate Physical and Human Geography , GC Leong (Oxford University press 3rd ed.) > Chapter 2: The Earth's Crust > The International Date Line > p. 14