QUES: As in the Scheiner system, speeds were expressed in 'degrees'. Originally the sensitivity was written as a fraction with 'tenths' (for example "18/10 DIN"), where the resultant value 1.8 represented the relative base 10 logarithm of the speed. 'Tenths' were later abandoned with DIN 4512:1957-11, and the example above would be written as "18 DIN". The degree symbol was finally dropped with DIN 4512:1961-10. This revision also saw significant changes in the definition of film speeds in order to accommodate then-recent changes in the American ASA PH2.5-1960 standard, so that film speeds of black-and-white negative film effectively would become doubled, that is, a film previously marked as "18 DIN" would now be labeled as "21 DIN" without emulsion changes.

How was sensitivity expressed at first in the DIN system?
What is the answer?
ANS: as a fraction with 'tenths' (for example "18/10 DIN")
QUES: The city also had a large class of free people of color. By 1860, 3,785 free people of color were in Charleston, nearly 18% of the city's black population, and 8% of the total population. Free people of color were far more likely to be of mixed racial background than slaves. Many were educated, practiced skilled crafts, and some even owned substantial property, including slaves. In 1790, they established the Brown Fellowship Society for mutual aid, initially as a burial society. It continued until 1945.

In what year was the Brown Fellowship Society ended?
What is the answer?
ANS: unanswerable
QUES: Ethnically and linguistically the population of the Republic of the Congo is diverseEthnologue recognises 62 spoken languages in the countrybut can be grouped into three categories. The Kongo are the largest ethnic group and form roughly half of the population. The most significant subgroups of the Kongo are Laari in Brazzaville and Pool regions and Vili around Pointe-Noire and along the Atlantic coast. The second largest group are the Teke who live to the north of Brazzaville with 17% of the population. Boulangui (M'Boshi) live in the northwest and in Brazzaville and form 12% of the population. Pygmies make up 2% of Congo's population.

What percentage of the population of the Congo is Boulangui?
What is the answer?
ANS:
12%