Which place is the authentic time of India determined?

In the given Venn diagram, the ‘circle’ represents ‘ladies’, the ‘triangle’ represents ‘teachers’, and the ‘rectangle’ represents ‘unmarried person’. The numbers given in the diagram represent the number of persons in that particular category.
How many married ladies are teachers?

In wich year was the International Date Line determined?

Greenwich is in which country?

Where does the international date line pass through?

Which of the following countries does not pass through the Tropic of Cancer?

Which one of the following cities is closest to the equator?

What is the number of longitudes?