The ASA standard underwent a major revision in 1960 with ASA PH2.5-1960, when the method to determine film speed was refined and previously applied safety factors against under-exposure were abandoned, effectively doubling the nominal speed of many black-and-white negative films. For example, an Ilford HP3 that had been rated at 200 ASA before 1960 was labeled 400 ASA afterwards without any change to the emulsion. Similar changes were applied to the DIN system with DIN 4512:1961-10 and the BS system with BS 1380:1963 in the following years.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): The nominal speed of what films were halved by abandoning safety factors?
Ah, so.. unanswerable

The Aravalli Range runs across the state from the southwest peak Guru Shikhar (Mount Abu), which is 1,722 m in height, to Khetri in the northeast. This range divides the state into 60% in the northwest of the range and 40% in the southeast. The northwest tract is sandy and unproductive with little water but improves gradually from desert land in the far west and northwest to comparatively fertile and habitable land towards the east. The area includes the Thar Desert. The south-eastern area, higher in elevation (100 to 350 m above sea level) and more fertile, has a very diversified topography. in the south lies the hilly tract of Mewar. In the southeast, a large area within the districts of Kota and Bundi forms a tableland. To the northeast of these districts is a rugged region (badlands) following the line of the Chambal River. Farther north the country levels out; the flat plains of the northeastern Bharatpur district are part of an alluvial basin. Merta City lies in the geographical center of Rajasthan.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): What percentage of Rajasthan is to the northwest of the Aravalli range?
Ah, so.. 60%

The American bison is a large bovid which inhabited much of western North America prior to the 1800s, living on the prairies in large herds. However, the vast herds of bison attracted market hunters, who killed dozens of bison for their hides only, leaving the rest to rot. Thousands of these hunters quickly eliminated the bison herds, bringing the population from several million in the early 1800s to a few hundred by the 1880s. Conservation efforts have allowed the population to increase, but the bison remains near-threatened.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): What type of creature is the American bison?
Ah, so..
a large bovid