Question: Eritrea (/ˌɛrᵻˈtreɪ.ə/ or /ˌɛrᵻˈtriːə/;, officially the State of Eritrea, is a country in East Africa. With its capital at Asmara, it is bordered by Sudan in the west, Ethiopia in the south, and Djibouti in the southeast. The northeastern and eastern parts of Eritrea have an extensive coastline along the Red Sea. The nation has a total area of approximately 117,600 km2 (45,406 sq mi), and includes the Dahlak Archipelago and several of the Hanish Islands. Its name Eritrea is based on the Greek name for the Red Sea (Ἐρυθρὰ Θάλασσα Erythra Thalassa), which was first adopted for Italian Eritrea in 1890.
Is there an answer to this question: What is the total area of the Red Sea?

Answer: unanswerable


Question: Two years later, the Royal African Company was inaugurated, receiving from King Charles a monopoly of the trade to supply slaves to the British colonies of the Caribbean. From the outset, slavery was the basis of the British Empire in the West Indies. Until the abolition of the slave trade in 1807, Britain was responsible for the transportation of 3.5 million African slaves to the Americas, a third of all slaves transported across the Atlantic. To facilitate this trade, forts were established on the coast of West Africa, such as James Island, Accra and Bunce Island. In the British Caribbean, the percentage of the population of African descent rose from 25 percent in 1650 to around 80 percent in 1780, and in the 13 Colonies from 10 percent to 40 percent over the same period (the majority in the southern colonies). For the slave traders, the trade was extremely profitable, and became a major economic mainstay for such western British cities as Bristol and Liverpool, which formed the third corner of the so-called triangular trade with Africa and the Americas. For the transported, harsh and unhygienic conditions on the slaving ships and poor diets meant that the average mortality rate during the Middle Passage was one in seven.
Is there an answer to this question: When was the British slave trade abolished?

Answer: 1807


Question: The largest single execution in United States history was the hanging of 38 American Indians convicted of murder and rape during the Dakota War of 1862. They were executed simultaneously on December 26, 1862, in Mankato, Minnesota. A single blow from an axe cut the rope that held the large four-sided platform, and the prisoners (except for one whose rope had broken and who had to be re-hanged) fell to their deaths. The second-largest mass execution was also a hanging: the execution of 13 African-American soldiers for taking part in the Houston Riot of 1917. The largest non-military mass execution occurred in one of the original thirteen colonies in 1723, when 26 convicted pirates were hanged in Newport, Rhode Island by order of the Admiralty Court.
Is there an answer to this question: What was the ethnicity of the people executed in the second-smallest mass execution in US history?

Answer: unanswerable


Question: In the United States, heating, ventilation and air conditioning (HVAC) systems account for 30% (4.65 EJ/yr) of the energy used in commercial buildings and nearly 50% (10.1 EJ/yr) of the energy used in residential buildings. Solar heating, cooling and ventilation technologies can be used to offset a portion of this energy.
Is there an answer to this question: How much energy does an HVAC system use in commercial locations?

Answer:
30% (4.65 EJ/yr)