Problem: Copper:

The concentration of copper in ores averages only 0.6%, and most commercial ores are sulfides, especially chalcopyrite (CuFeS2) and to a lesser extent chalcocite (Cu2S). These minerals are concentrated from crushed ores to the level of 1015% copper by froth flotation or bioleaching. Heating this material with silica in flash smelting removes much of the iron as slag. The process exploits the greater ease of converting iron sulfides into its oxides, which in turn react with the silica to form the silicate slag, which floats on top of the heated mass. The resulting copper matte consisting of Cu2S is then roasted to convert all sulfides into oxides:

What is the average concentration of copper in holes?
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A: unanswerable

Problem: There are scouting and guiding groups on Saint Helena and Ascension Island. Scouting was established on Saint Helena island in 1912. Lord and Lady Baden-Powell visited the Scouts on Saint Helena on the return from their 1937 tour of Africa. The visit is described in Lord Baden-Powell's book entitled African Adventures.
Who visited the scouts on their return from the tour of Africa in 1937?
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Answer: Lord and Lady Baden-Powell

Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
After several years of economic downturn and political instability, in 1997, Guinea-Bissau entered the CFA franc monetary system, bringing about some internal monetary stability. The civil war that took place in 1998 and 1999, and a military coup in September 2003 again disrupted economic activity, leaving a substantial part of the economic and social infrastructure in ruins and intensifying the already widespread poverty. Following the parliamentary elections in March 2004 and presidential elections in July 2005, the country is trying to recover from the long period of instability, despite a still-fragile political situation.
In what year did Guinea-Bissau start to bring some internal monetary stability to the country?
A: 1997

Context and question: Scholars and historians are divided as to what event signals the end of the Hellenistic era. The Hellenistic period may be seen to end either with the final conquest of the Greek heartlands by Rome in 146 BC following the Achean War, with the final defeat of the Ptolemaic Kingdom at the Battle of Actium in 31 BC, or even the move by Roman emperor Constantine the Great of the capital of the Roman Empire to Constantinople in 330 AD. "Hellenistic" is distinguished from "Hellenic" in that the first encompasses the entire sphere of direct ancient Greek influence, while the latter refers to Greece itself.
Who was the Roman emporer?
Answer: Constantine the Great

Question: When an inductive circuit is opened, the current through the inductance collapses quickly, creating a large voltage across the open circuit of the switch or relay. If the inductance is large enough, the energy will generate a spark, causing the contact points to oxidize, deteriorate, or sometimes weld together, or destroying a solid-state switch. A snubber capacitor across the newly opened circuit creates a path for this impulse to bypass the contact points, thereby preserving their life; these were commonly found in contact breaker ignition systems, for instance. Similarly, in smaller scale circuits, the spark may not be enough to damage the switch but will still radiate undesirable radio frequency interference (RFI), which a filter capacitor absorbs. Snubber capacitors are usually employed with a low-value resistor in series, to dissipate energy and minimize RFI. Such resistor-capacitor combinations are available in a single package.
Is there an answer to this question: What is a typical system in which a snubber capacitor is not found?

Answer: unanswerable

QUES: Evidence from the early technical literature concerning electrical recording suggests that it wasn't until the 19421949 period that there were serious efforts to standardize recording characteristics within an industry. Heretofore, electrical recording technology from company to company was considered a proprietary art all the way back to the 1925 Western Electric licensed method used by Columbia and Victor. For example, what Brunswick-Balke-Collender (Brunswick Corporation) did was different from the practices of Victor.

How was standardization prior to 1942?
What is the answer?
ANS:
considered a proprietary art