Context and question: Copper has been in use at least 10,000 years, but more than 95% of all copper ever mined and smelted has been extracted since 1900, and more than half was extracted in only the last 24 years. As with many natural resources, the total amount of copper on Earth is vast (around 1014 tons just in the top kilometer of Earth's crust, or about 5 million years' worth at the current rate of extraction). However, only a tiny fraction of these reserves is economically viable, given present-day prices and technologies. Various estimates of existing copper reserves available for mining vary from 25 years to 60 years, depending on core assumptions such as the growth rate. Recycling is a major source of copper in the modern world. Because of these and other factors, the future of copper production and supply is the subject of much debate, including the concept of peak copper, analogous to peak oil.
What percentage of copper has been stolen since 1900?
Answer: unanswerable
Context and question: PS3's hardware has also been used to build supercomputers for high-performance computing. Fixstars Solutions sells a version of Yellow Dog Linux for PlayStation 3 (originally sold by Terra Soft Solutions). RapidMind produced a stream programming package for PS3, but were acquired by Intel in 2009. Also, on January 3, 2007, Dr. Frank Mueller, Associate Professor of Computer science at NCSU, clustered 8 PS3s. Mueller commented that the 256 MB of system RAM is a limitation for this particular application and is considering attempting to retrofit more RAM. Software includes: Fedora Core 5 Linux ppc64, MPICH2, OpenMP v 2.5, GNU Compiler Collection and CellSDK 1.1. As a more cost-effective alternative to conventional supercomputers, the U.S. military has purchased clusters of PS3 units for research purposes. Retail PS3 Slim units cannot be used for supercomputing, because PS3 Slim lacks the ability to boot into a third-party OS.
How many PlayStation 3 consoles was Dr. Frank Mueller able to cluster together?
Answer: 8
Context and question: It is estimated that there are around 100 elephants left in Eritrea, the most northerly of East Africa's elephants. The endangered African wild dog (Lycaon pictus) was previously found in Eritrea, but is now deemed extirpated from the entire country. In Gash Barka, deadly snakes like saw-scaled viper are common. Puff adder and red spitting cobra are widespread and can be found even in the highlands.In the coastal areas marine species that are common include dolphin, dugong, whale shark, turtles, marlin/swordfish, and manta ray.
Where are the most southerly of East Africa's elephants to be found?
Answer:
unanswerable