Calculate the local time in New York (75°W) when it is 10 a.m. in Nigeria (15°E)?

• The longitudinal difference between New York and Nigeria is: 75° + 15° = 90°
• For 1° longitudinal difference time difference is 4 minutes.
• So, for 90° longitudinal difference, the time difference is: 90° x 4 = 360 minutes or 6 hours.
• As New York is situated in the west of Nigeria, the local time at New York will be: ( 10 a.m. - 6 hours) = 4 a.m.