The ASVAB currently contains 9 sections (except the written test, which contains 8 sections). The duration of each test varies from as low as ten minutes up to 36 minutes for Arithmetic Reasoning; the entire ASVAB is three hours long. The test is typically administered in a computerized format at Military Entrance Processing Stations, known as MEPS, or at a satellite location called a Military Entrance Test (MET) site. The ASVAB is administered by computer at the MEPS, while a written version is given at most MET sites. Testing procedures vary depending on the mode of administration.[3]

The scores from the other tests are used to determine what type of specialty you might be best suited for.  These "composite" scores (also known as line scores, MOS scores, or aptitude area scores) are calculated by adding together combinations of the different sub test standard scores. These composite scores are then used to determine which different military jobs (aka Military Occupational Specialties or MOS) may be the best fit for you.  Each branch of the military will have their own approach to these composite scores.

Either because of the cultural memory, national history, or the potentiality of a military threat, the militarist argument asserts that a civilian population is dependent upon, and thereby subservient to the needs and goals of its military for continued independence. Militarism is sometimes contrasted with the concepts of comprehensive national power, soft power and hard power.
Just as the President, the Secretary of Defense, and the Secretary of Homeland Security, are in charge of the entire military establishment, maintaining civilian control of the military, so too are each of the Defense Department's constitutive military departments headed by civilians. The four DoD branches are organized into three departments, each with civilian heads. The Department of the Army is headed by the Secretary of the Army, the Department of the Navy is headed by the Secretary of the Navy and the Department of the Air Force is headed by the Secretary of the Air Force. The Marine Corps is organized under the Department of the Navy, however it is still considered a separate and equal service. The Coast Guard is under the Department of Homeland Security and receives its operational orders from the Secretary of Homeland Security. However, the Coast Guard may be transferred to the Department of the Navy by the President or Congress during a time of war, thereby placing it within the DoD.[19]
Individuals can also complete a computer version of the test. This is an adaptive test, meaning the difficulty level of each question is determined based on whether the previous question was answered correctly or incorrectly. Aside from the fact that this version of the AFQT is a computer adaptive test, the number of questions that must be answered varies from the written version of the assessment. Individuals only need to answer a total of 59 questions. 89 minutes is allotted for the four sections of the Armed Forces Qualification Test, and test-takers typically have more than enough time to complete each section.

I just had to thank you guys for the test prep! I am a former Marine that decided to reenter the military and much to my surprise, I had to retake the AFQT!!! The last time I even looked at a math or English problem had to be at least 6 or seven years ago. I bought the guide as a last minute prep, I mean maybe 5 hours before the test. Like I said, I didn't even know I had to retake the test and had ZERO preparation! The job I wanted required a pretty high GT score and I was nervous about even passing the test let alone receiving the score I needed. I read the guide through only once before test time and needless to say, the only way I passed was thanks to your refresher!! Sgt. Brian

The scores from the other tests are used to determine what type of specialty you might be best suited for.  These "composite" scores (also known as line scores, MOS scores, or aptitude area scores) are calculated by adding together combinations of the different sub test standard scores. These composite scores are then used to determine which different military jobs (aka Military Occupational Specialties or MOS) may be the best fit for you.  Each branch of the military will have their own approach to these composite scores.

The results of each test are shown as soon as you complete it. You’ll see what you got right and how it compares to other people who took the same test. Feedback is also visual, showing your percentile and success on each question compared to others. The answers to each ASVAB practice test question are explained as well. The free ASVAB example questions are both tools for learning and for comparing your results to your own previous attempts, and to the scores of your classmates and peers. You can use the scores as a baseline and to identify your weaknesses. With this information, it becomes easier to focus your study time and effort on areas that need improvement.
The test must be completed if you wish to serve in the Army, Navy, Marines, Air Force, or Coast Guard. The test can also be taken as a career-exploration tool if you are a high school sophomore, junior, or senior. It takes approximately three hours to complete. If you take the computerized version of the test, results are given immediately. If you complete a paper and pencil test, you’ll get results within two weeks.
A century or so later, in the hands of writers such as Jean Froissart, Miguel Cervantes and William Shakespeare, the fictional knight Tirant lo Blanch, and the real-life condottieri John Hawkwood would be juxtaposed against the fantastical Don Quixote, and the carousing Sir John Falstaff. In just one play, Henry V, Shakespeare provides a whole range of military characters, from cool-headed and clear-sighted generals, to captains, and common soldiery.
In Medieval Europe, tales of knighthood and chivalry, the officer class of the period captured the popular imagination. Writers and poets like Taliesin, Chrétien de Troyes and Thomas Malory wrote tales of derring-do, featuring Arthur, Guinevere, Lancelot and Galahad. Even in the 21st century, books and films about the Arthurian legend and the Holy Grail continue to appear.
The military uses the verbal expression (VE) score to measure your communicative ability. The score goes toward computing the AFQT score as well as many of the military’s line scores. The military brass determine your VE score by first adding the value of your Word Knowledge (WK) raw score to your Paragraph Comprehension (PC) raw score. The result is then converted to a scaled score ranging from 20 to 62.
The ASVAB is a population-referenced exam, which means that the score you receive for the ASVAB is not an exact measure of how you scored on the test, but rather how you scored in relation to a national control group who took the test in 1997. Standard Scores are used on the ASVAB: in each subtest, about 50% of the population received a Standard Score of 50, while only 16% scored over 60. You will receive an estimated score after taking the paper test and official scores later through your recruiter, usually within days. You will immediately receive your scores upon completing the computer test.
As of 31 December 2010, U.S. Armed Forces troops were stationed in 150 countries; the number of non-contingent deployments per country ranges from 1 in Suriname to over 50,000 in Germany.[30] Some of the largest deployments are: 103,700 in Afghanistan, 52,440 in Germany (see list), 35,688 in Japan (USFJ), 28,500 in South Korea (USFK), 9,660 in Italy and 9,015 in the United Kingdom. These numbers change frequently due to the regular recall and deployment of units.
If you’re planning on using your scores for military enlistment, you may be hoping to achieve a score that is high enough for a specific signing bonus. While it’s natural to want to do your best, putting extra pressure on yourself can cause unnecessary anxiety. Take a few deep breaths, relax, and remember that taking the test is only part of the entire recruitment process.
Your performance in four basic areas – Arithmetic Reasoning (AR), Mathematics Knowledge (MK), Paragraph Comprehension (PC), and Word Knowledge (WK) determines whether you’ve made the grade. Your scores in the AR, MK, and Verbal Composite (VE, which is WK+PC) sections add up to the all-important “AFQT” (Armed Forces Qualifying Test) score that recruiters use to see if you are eligible to serve.
Don’t be fooled by the appearance of the low numbers, the algorithm that computes the AFQT is very sophisticated. Just because your ASVAB score is 40 doesn’t mean that you only got 40% of the questions correct, it could simply mean that you lack strength in one area, but succeed with high praise in another. Your ASVAB score is only a means by which you are categorized for available positions; it is by no means a measure of intelligence.
Word Knowledge (WK), Paragraph Comprehension (PC), Arithmetic Reasoning (AR), and Mathematics Knowledge (MK). Scores on the AFQT are used to determine your eligibility for enlistment in the Army, Navy, Air Force, or Marine Corps. The other six test scores on the ASVAB tests are used to determine the best job for you in the military as your grades will demonstrate knowledge, skill, and interest in certain subjects and tasks. 
A lot of people see the “CAT” term attached to the ASVAB test when they first start looking into the test and aren’t sure what that stands for. This term is an acronym and it stands for “Computerized Adaptive Test”. There are three different versions of the ASVAB test. The CAT is available at military processing stations for enlisting soldiers. The pencil and paper (also known as the P&P or S-ASVAB) version of the test is available for high school and college students who may not actually enlist. The third type of ASVAB test is the MET-ASVAB, or Mobile Examination Test, which is available only for enlisted soldiers at mobile testing centers (this test is also done with paper and pencil).
The obligations of military employment are many. Full-time military employment normally requires a minimum period of service of several years; between two and six years is typical of armed forces in Australia, the UK and the US, for example, depending on role, branch, and rank.[19][20][21] Some armed forces allow a short discharge window, normally during training, when recruits may leave the armed force as of right.[22] Alternatively, part-time military employment, known as reserve service, allows a recruit to maintain a civilian job while training under military discipline at weekends; he or she may be called out to deploy on operations to supplement the full-time personnel complement. After leaving the armed forces, recruits may remain liable for compulsory return to full-time military employment in order to train or deploy on operations.[22][21]

AFQT scores are the primary measure of recruit potential. Figure 2.7 indicates the percentage of NPS recruits who scored at or above the 50th percentile (Categories I–IIIA) since FY 1973. Numerical data are in Appendix D, Table D-12. The drop in Category I–IIIA recruits after FY 1976 was due primarily to the miscalibration of the ASVAB. [1] In FY 1976, when new versions of the ASVAB were introduced, an error in calibrating the score scales made the new versions "easier" than the old versions (i.e., applicants received test scores higher than their actual ability). In FY 1980, an independent study of the calibration was made and the test was correctly calibrated. Then, Congress added legal provisions stipulating that no more than 20 percent of accessions could be in Category IV and that such accessions had to be high school diploma graduates. [2] However, as previously stated, Defense Planning Guidance decreases this limit even further, allowing no more than 4 percent of recruits to come from Category IV.
The Armed Forces Qualification Test (AFQT) is used by all of the Services to determine if an applicant is eligible for the military. Four of the ASVAB subtests are combined to form the AFQT. It measures general cognitive ability and is composed of verbal and mathematics subtests. AFQT scores are grouped into categories for reporting purposes. The table below shows the AFQT categories and the percentile score ranges corresponding to the categories. Applicants that score in AFQT category IIIA or higher may qualify for enlistment incentives.