Input: Read this: 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.
Question: How much copper is estimated to be missing on earth?

Output: unanswerable

Input: Read this: There has, however, been interest among railroad operators in returning to DC use at higher voltages than previously used. At the same voltage, DC often has less loss than AC, and for this reason high-voltage direct current is already used on some bulk power transmission lines. DC avoids the electromagnetic radiation inherent with AC, and on a railway this also reduces interference with signalling and communications and mitigates hypothetical EMF risks. DC also avoids the power factor problems of AC. Of particular interest to railroading is that DC can supply constant power with a single ungrounded wire. Constant power with AC requires three-phase transmission with at least two ungrounded wires. Another important consideration is that mains-frequency 3-phase AC must be carefully planned to avoid unbalanced phase loads. Parts of the system are supplied from different phases on the assumption that the total loads of the 3 phases will even out. At the phase break points between regions supplied from different phases, long insulated supply breaks are required to avoid them being shorted by rolling stock using more than one pantograph at a time. A few railroads have tried 3-phase but its substantial complexity has made single-phase standard practice despite the interruption in power flow that occurs twice every cycle. An experimental 6 kV DC railway was built in the Soviet Union.
Question: Where was an experimental 6kV DC railway built?

Output: the Soviet Union

Input: Read this: LeToya Luckett and Roberson became unhappy with Mathew's managing of the band and eventually were replaced by Farrah Franklin and Michelle Williams. Beyonce experienced depression following the split with Luckett and Roberson after being publicly blamed by the media, critics, and blogs for its cause. Her long-standing boyfriend left her at this time. The depression was so severe it lasted for a couple of years, during which she occasionally kept herself in her bedroom for days and refused to eat anything. Beyonce stated that she struggled to speak about her depression because Destiny's Child had just won their first Grammy Award and she feared no one would take her seriously. Beyonce would later speak of her mother as the person who helped her fight it. Franklin was dismissed, leaving just Beyonce, Rowland, and Williams.
Question: Who replaced Luckett and Roberson in Destiny's Child?

Output: Farrah Franklin and Michelle Williams.

Input: Read this: On May 21, 2014, JPMorgan Chase announced that it was injecting $100 million over five years into Detroit's economy, providing development funding for a variety of projects that would increase employment. It is the largest commitment made to any one city by the nation's biggest bank.[citation needed] Of the $100 million, $50 million will go toward development projects, $25 million will go toward city blight removal, $12.5 million will go for job training, $7 million will go for small businesses in the city, and $5.5 million will go toward the M-1 light rail project. On May 19, 2015, JPMorgan Chase announced that it has invested $32 million for two redevelopment projects in the city's Capitol Park district, the Capitol Park Lofts (the former Capitol Park Building) and the Detroit Savings Bank building at 1212 Griswold. Those investments are separate from Chase's five-year, $100-million commitment.
Question: How much did JPMorgan announce in additional investment into Detroit in 2015?

Output:
$32 million