Problem: The logical format of an audio CD (officially Compact Disc Digital Audio or CD-DA) is described in a document produced in 1980 by the format's joint creators, Sony and Philips. The document is known colloquially as the Red Book CD-DA after the colour of its cover. The format is a two-channel 16-bit PCM encoding at a 44.1 kHz sampling rate per channel. Four-channel sound was to be an allowable option within the Red Book format, but has never been implemented. Monaural audio has no existing standard on a Red Book CD; thus, mono source material is usually presented as two identical channels in a standard Red Book stereo track (i.e., mirrored mono); an MP3 CD, however, can have audio file formats with mono sound.
Do CDs have a two or four channel format?
The answer is the following: two-channel

Problem: Because of the global economic recession that began in 2007, the GDP of Estonia decreased by 1.4% in the 2nd quarter of 2008, over 3% in the 3rd quarter of 2008, and over 9% in the 4th quarter of 2008. The Estonian government made a supplementary negative budget, which was passed by Riigikogu. The revenue of the budget was decreased for 2008 by EEK 6.1 billion and the expenditure by EEK 3.2 billion. In 2010, the economic situation stabilized and started a growth based on strong exports. In the fourth quarter of 2010, Estonian industrial output increased by 23% compared to the year before. The country has been experiencing economic growth ever since.
When did the global economic recession start?
The answer is the following: 2007

Problem: Matte solder is usually fused to provide a better bonding surface or stripped to bare copper. Treatments, such as benzimidazolethiol, prevent surface oxidation of bare copper. The places to which components will be mounted are typically plated, because untreated bare copper oxidizes quickly, and therefore is not readily solderable. Traditionally, any exposed copper was coated with solder by hot air solder levelling (HASL). The HASL finish prevents oxidation from the underlying copper, thereby guaranteeing a solderable surface. This solder was a tin-lead alloy, however new solder compounds are now used to achieve compliance with the RoHS directive in the EU and US, which restricts the use of lead. One of these lead-free compounds is SN100CL, made up of 99.3% tin, 0.7% copper, 0.05% nickel, and a nominal of 60ppm germanium.
What's the process by which bare copper gets covered in solder?
The answer is the following: hot air solder levelling

Problem: In 2007, about 48 percent of Malians were younger than 12 years old, 49 percent were 15–64 years old, and 3 percent were 65 and older. The median age was 15.9 years. The birth rate in 2014 is 45.53 births per 1,000, and the total fertility rate (in 2012) was 6.4 children per woman. The death rate in 2007 was 16.5 deaths per 1,000. Life expectancy at birth was 53.06 years total (51.43 for males and 54.73 for females). Mali has one of the world's highest rates of infant mortality, with 106 deaths per 1,000 live births in 2007.
For both men and women average life expectancy is how many years?
The answer is the following:
53.06