QUES: In the example above, the identity and the rotations constitute a subgroup R = {id, r1, r2, r3}, highlighted in red in the group table above: any two rotations composed are still a rotation, and a rotation can be undone by (i.e. is inverse to) the complementary rotations 270 for 90, 180 for 180, and 90 for 270 (note that rotation in the opposite direction is not defined). The subgroup test is a necessary and sufficient condition for a subset H of a group G to be a subgroup: it is sufficient to check that g1h H for all elements g, h H. Knowing the subgroups is important in understanding the group as a whole.d["]

What is defined when moving in the opposite direction?
What is the answer?
ANS: unanswerable
QUES: The paper is then fed onto reels if it is to be used on web printing presses, or cut into sheets for other printing processes or other purposes. The fibres in the paper basically run in the machine direction. Sheets are usually cut "long-grain", i.e. with the grain parallel to the longer dimension of the sheet.

What is the paper fed onto unless it is going to be cut into sheets?
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%