Problem: On October 22, 2007, Apple reported quarterly revenue of US$6.22 billion, of which 30.69% came from Apple notebook sales, 19.22% from desktop sales and 26% from iPod sales. Apple's 2007 year revenue increased to US$24.01 billion with US$3.5 billion in profits. Apple ended the fiscal year 2007 with US$15.4 billion in cash and no debt.
Desktop computers made up how much of Apple's revenue in the third quarter of 2007?
The answer is the following: 19.22%

Problem: The spectrum emitted by a blackbody radiator at temperatures of incandescent bulbs does not match the sensitivity characteristics of the human eye; the light emitted does not appear white, and most is not in the range of wavelengths at which the eye is most sensitive. Tungsten filaments radiate mostly infrared radiation at temperatures where they remain solid – below 3,695 K (3,422 °C; 6,191 °F). Donald L. Klipstein explains it this way: "An ideal thermal radiator produces visible light most efficiently at temperatures around 6,300 °C (6,600 K; 11,400 °F). Even at this high temperature, a lot of the radiation is either infrared or ultraviolet, and the theoretical luminous efficacy (LER) is 95 lumens per watt." No known material can be used as a filament at this ideal temperature, which is hotter than the sun's surface. An upper limit for incandescent lamp luminous efficacy (LER) is around 52 lumens per watt, the theoretical value emitted by tungsten at its melting point.
What is the upper limit for LER of an incandescent lamp?
The answer is the following: 52 lumens per watt

Problem: Furthermore, the amount of time adolescents spend on work and leisure activities varies greatly by culture as a result of cultural norms and expectations, as well as various socioeconomic factors. American teenagers spend less time in school or working and more time on leisure activities—which include playing sports, socializing, and caring for their appearance—than do adolescents in many other countries. These differences may be influenced by cultural values of education and the amount of responsibility adolescents are expected to assume in their family or community.
Do American teenagers spend more or less time on leisure activities than adolescents in other countries?
The answer is the following: more

Problem: The North Slope is mostly tundra peppered with small villages. The area is known for its massive reserves of crude oil, and contains both the National Petroleum Reserve–Alaska and the Prudhoe Bay Oil Field. Barrow, the northernmost city in the United States, is located here. The Northwest Arctic area, anchored by Kotzebue and also containing the Kobuk River valley, is often regarded as being part of this region. However, the respective Inupiat of the North Slope and of the Northwest Arctic seldom consider themselves to be one people.
What is the northernmost city in the US?
The answer is the following:
Barrow