Questions

The atmospheric pressure at the surface of the Earth is due to gravitational pull of the earth and is about 14.7 psi.

That means that the weight of a column of air which has a cross section of 1 square inch and which stretches from the surface of the Earth to space is 14.7 pounds. 

Fahien came to India during the reign of Chandragupta Vikramaditya.

The puzzle's logic is

1st figure : (9-7) + (8-5) = 2 + 3 = 5

2nd figure : (15-6) + (11-2) = 9 + 9 = 18

similarly, 3rd figure : (9-6) + (17-5) = 3 + 12 = 15.

The series number is found in both the upper right margin and the lower left margin. It is a sequence reference expressed either as a four-digit numeral (1125) or as a letter, followed by a three- or four-digit numeral (M661, T7110).