Article: Persistent heavy rain and landslides in Wenchuan County and the nearby area badly affected rescue efforts. At the start of rescue operations on May 12, 20 helicopters were deployed for the delivery of food, water, and emergency aid, and also the evacuation of the injured and reconnaissance of quake-stricken areas. By 17:37 CST on May 13, a total of over 15,600 troops and militia reservists from the Chengdu Military Region had joined the rescue force in the heavily affected areas. A commander reported from Yingxiu Town, Wenchuan, that around 3,000 survivors were found, while the status of the other inhabitants (around 9,000) remained unclear. The 1,300 rescuers reached the epicenter, and 300 pioneer troops reached the seat of Wenchuan at about 23:30 CST. By 12:17 CST, May 14, 2008, communication in the seat of Wenchuan was partly revived. On the afternoon of May 14, 15 Special Operations Troops, along with relief supplies and communications gear, parachuted into inaccessible Mao County, northeast of Wenchuan.

Question: How many helicopters were deployed?
Ans: 20

Here is a question about this article: On the other hand, classical (analog) television transmissions are usually horizontally polarized, because in urban areas buildings can reflect the electromagnetic waves and create ghost images due to multipath propagation. Using horizontal polarization, ghosting is reduced because the amount of reflection of electromagnetic waves in the p polarization (horizontal polarization off the side of a building) is generally less than s (vertical, in this case) polarization. Vertically polarized analog television has nevertheless been used in some rural areas. In digital terrestrial television such reflections are less problematic, due to robustness of binary transmissions and error correction.
What is the answer to this question: What is another name for classical television transmissions?
****
So... analog

The problem: Answer a question about this article:
At its greatest extent, the Achaemenid Empire included the modern territories of Iran, Azerbaijan, Armenia, Georgia, Turkey, much of the Black Sea coastal regions, northeastern Greece and southern Bulgaria (Thrace), northern Greece and Macedonia (Paeonia and Ancient Macedon), Iraq, Syria, Lebanon, Jordan, Israel, Palestine, all significant ancient population centers of ancient Egypt as far west as Libya, Kuwait, northern Saudi Arabia, parts of the UAE and Oman, Pakistan, Afghanistan, and much of Central Asia, making it the first world government and the largest empire the world had yet seen.
What was the largest empire the world had seen at the time it existed?
****
The answer: the Achaemenid Empire

Problem: Please answer a question about the following article about MP3:
A sample rate of 44.1 kHz is almost always used, because this is also used for CD audio, the main source used for creating MP3 files. A greater variety of bit rates are used on the Internet. The rate of 128 kbit/s is commonly used, at a compression ratio of 11:1, offering adequate audio quality in a relatively small space. As Internet bandwidth availability and hard drive sizes have increased, higher bit rates up to 320 kbit/s are widespread.
The common bit rate on the internet is 128 kbit/s using which compression ratio?
A: 11:1

Question: Read this and answer the question

In 1999, Estonia experienced its worst year economically since it regained independence in 1991, largely because of the impact of the 1998 Russian financial crisis.[citation needed] Estonia joined the WTO in November 1999. With assistance from the European Union, the World Bank and the Nordic Investment Bank, Estonia completed most of its preparations for European Union membership by the end of 2002 and now has one of the strongest economies of the new member states of the European Union.[citation needed] Estonia joined the OECD in 2010.

When did Estonia unite with the WTO?
Answer: November 1999

Originally the Emperor and non-warrior nobility employed these warrior nobles. In time, they amassed enough manpower, resources and political backing in the form of alliances with one another, to establish the first samurai-dominated government. As the power of these regional clans grew, their chief was typically a distant relative of the Emperor and a lesser member of either the Fujiwara, Minamoto, or Taira clans. Though originally sent to provincial areas for a fixed four-year term as a magistrate, the toryo declined to return to the capital when their terms ended, and their sons inherited their positions and continued to lead the clans in putting down rebellions throughout Japan during the middle- and later-Heian period. Because of their rising military and economic power, the warriors ultimately became a new force in the politics of the court. Their involvement in the Hogen in the late Heian period consolidated their power, and finally pitted the rival Minamoto and Taira clans against each other in the Heiji Rebellion of 1160.
Who fought in the Heiji Rebellion?
the rival Minamoto and Taira clans