You are studying in a school which is located at 45° West longitude. How many hours are you behind from your family in Bhutan?

45° West longitude - somewhere in South America (may be Brazil).

To calculate the time difference between the school and the family in Bhutan, we need to take into account the first time zone located in Greenwich, London, United Kingdom.

Between the time zone corresponding to the first meridian and the location of the school = 3 hours

Between the first meridian and the location of the family in Bhutan = 6 hours

So, the difference in hours between the school where I study and the family in Bhutan = 9 hours.