Problem: Mithridates the Great was the ruler of Pontus, a large kingdom in Asia Minor (modern Turkey), from 120 to 63 BC. Mithridates antagonised Rome by seeking to expand his kingdom, and Rome for her part seemed equally eager for war and the spoils and prestige that it might bring. In 88 BC, Mithridates ordered the killing of a majority of the 80,000 Romans living in his kingdom. The massacre was the official reason given for the commencement of hostilities in the First Mithridatic War. The Roman general Lucius Cornelius Sulla forced Mithridates out of Greece proper, but then had to return to Italy to answer the internal threat posed by his rival, Gaius Marius. A peace was made between Rome and Pontus, but this proved only a temporary lull.
Who was the leader of Pontus in the year 85 BC?
The answer is the following: Mithridates the Great

Problem: Because of the acceptance of miscegenation, Brazil has avoided the binary polarization of society into black and white. In addition, it abolished slavery without a civil war. The bitter and sometimes violent racial tensions that have divided the US are notably absent in Brazil. According to the 2010 census, 6.7% of Brazilians said they were black, compared with 6.2% in 2000, and 43.1% said they were racially mixed, up from 38.5%. In 2010, Elio Ferreira de Araujo, Brazil's minister for racial equality, attributed the increases to growing pride among his country's black and indigenous communities.
Who is responsible for the growing pride in Brazilian communities?
The answer is the following: black and indigenous communities.

Problem: Lamps designed for different voltages have different luminous efficacy. For example, a 100-watt, 120-volt lamp will produce about 17.1 lumens per watt. A lamp with the same rated lifetime but designed for 230 V would produce only around 12.8 lumens per watt, and a similar lamp designed for 30 volts (train lighting) would produce as much as 19.8 lumens per watt. Lower voltage lamps have a thicker filament, for the same power rating. They can run hotter for the same lifetime before the filament evaporates.
How many lumens per watt does a typical train light produce?
The answer is the following: as much as 19.8 lumens per watt

Problem: According to the U.S. Census Bureau, as of 2015, Tennessee had an estimated population of 6,600,299, which is an increase of 50,947, from the prior year and an increase of 254,194, or 4.01%, since the year 2010. This includes a natural increase since the last census of 142,266 people (that is 493,881 births minus 351,615 deaths), and an increase from net migration of 219,551 people into the state. Immigration from outside the United States resulted in a net increase of 59,385 people, and migration within the country produced a net increase of 160,166 people. Twenty percent of Tennesseans were born outside the South in 2008, compared to a figure of 13.5% in 1990.
How much of Tennessee's population increase between 2010 and 2015 was due to migration?
The answer is the following:
219,551