Short answers, pulled from the story.
Rupee derives from the Sanskrit word rūpya, meaning "wrought silver, a coin of silver." Rūpya in turn comes from rūpa, meaning "shape, likeness, or image." The word carried both a material description and an aesthetic one: stamped, formed silver.
Sher Shah Suri of the Sur Empire issued the silver rupiya during his reign from 1538 to 1545. The coin weighed 178 grains and was issued alongside copper coins called dam and gold coins called mohur weighing 169 grains (10.95 grams).
India decimalized the rupee on the 1st of April 1957, under the 1955 Indian Coinage Amendment Act. The rupee was divided into 100 paise, replacing the earlier system of 16 annas or 64 pice. Pakistan followed with its own decimalization in 1961.
India, Pakistan, Nepal, Sri Lanka, Mauritius, and Seychelles currently use currencies called the rupee. Indonesia uses the rupiah and the Maldives uses the rufiyaa, both cognates of the word rupee.
The Gulf rupee, also called the external rupee, was a separate currency created by India in 1959 to limit the smuggling of gold out of the country. It served as the official currency of Dubai and Qatar and remained legal tender until 1966, when India devalued the Indian rupee and both territories adopted a new Qatar-Dubai riyal.
The pig rupee was a coin issued following the 1911 accession of King-Emperor George V. The coin showed the king wearing a robe embossed with an elephant, but poor engraving made the elephant appear to look like a pig. The Muslim population was enraged and the image was quickly redesigned.