Question

CALCULATE THE TIME AT A PLACE A (30 DEG WEST) WHEN THE TIME AT A PLACE B (75 DEG EAST) IS 9 PM.

Answer 1

Longitude of Cairo = 30° E  Longitude of New York = 75° W  Difference in Longitude = 30° + 75° = 105°  (Add because Cairo is in the East of Greenwich and New York is in the West of Greenwich).  ∴ Difference in time = 105 × 4 = 420 minutes = 7 hours As New York is situated in the West of Greenwich, its local time will be behind that of Cairo. So we subtract.Read more on Sarthaks.com - https://www.sarthaks.com/147994/give-reasons-for-the-following-when-it-is-noon-at-cairo-30e-the-local-time-in-new-york-75w-is