Problem: Boston (pronounced i/bstn/) is the capital and largest city of the Commonwealth of Massachusetts in the United States. Boston also served as the historic county seat of Suffolk County until Massachusetts disbanded county government in 1999. The city proper covers 48 square miles (124 km2) with an estimated population of 655,884 in 2014, making it the largest city in New England and the 24th largest city in the United States. The city is the economic and cultural anchor of a substantially larger metropolitan area called Greater Boston, home to 4.7 million people and the tenth-largest metropolitan statistical area in the country. Greater Boston as a commuting region is home to 8.1 million people, making it the sixth-largest combined statistical area in the United States.
What is the estimated population of Greater Boston?
The answer is the following: 4.7 million people

Problem: Two Polish friends in Paris were also to play important roles in Chopin's life there. His fellow student at the Warsaw Conservatory, Julian Fontana, had originally tried unsuccessfully to establish himself in England; Albert Grzymaa, who in Paris became a wealthy financier and society figure, often acted as Chopin's adviser and "gradually began to fill the role of elder brother in [his] life." Fontana was to become, in the words of Michaowski and Samson, Chopin's "general factotum and copyist".
Julian Fontana tried to find his way where before moving to Paris?
The answer is the following: England

Problem: Canadian bitumen does not differ substantially from oils such as Venezuelan extra-heavy and Mexican heavy oil in chemical composition, and the real difficulty is moving the extremely viscous bitumen through oil pipelines to the refinery. Many modern oil refineries are extremely sophisticated and can process non-upgraded bitumen directly into products such as gasoline, diesel fuel, and refined asphalt without any preprocessing. This is particularly common in areas such as the US Gulf coast, where refineries were designed to process Venezuelan and Mexican oil, and in areas such as the US Midwest where refineries were rebuilt to process heavy oil as domestic light oil production declined. Given the choice, such heavy oil refineries usually prefer to buy bitumen rather than synthetic oil because the cost is lower, and in some cases because they prefer to produce more diesel fuel and less gasoline. By 2015 Canadian production and exports of non-upgraded bitumen exceeded that of synthetic crude oil at over 1.3 million barrels (21010^3 m3) per day, of which about 65% was exported to the United States.
Why do refineries like to buy bitumen instead of synthetic oil?
The answer is the following: cost is lower

Problem: Whites (mainly of Afrikaner, German, British and Portuguese origin) make up between 4.0 and 7.0% of the population. Although their percentage of population is decreasing due to emigration and lower birth rates they still form the second-largest population of European ancestry, both in terms of percentage and actual numbers, in Sub-Saharan Africa (after South Africa). The majority of Namibian whites and nearly all those who are mixed race speak Afrikaans and share similar origins, culture, and religion as the white and coloured populations of South Africa. A large minority of whites (around 30,000) trace their family origins back to the German settlers who colonized Namibia prior to the British confiscation of German lands after World War One, and they maintain German cultural and educational institutions. Nearly all Portuguese settlers came to the country from the former Portuguese colony of Angola. The 1960 census reported 526,004 persons in what was then South-West Africa, including 73,464 whites (14%).
Where do a large minority of whites trace their Namibian roots to?
The answer is the following:
German settlers