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.
To be admitted to the ASVAB testing room you will need to show a valid id. It is also important to be on time (or early!) since you will be turned away if you show up after the scheduled start time. The ASVAB can be given via computer or pencil and paper.  If you are testing at a MEPS site you will take it on a computer.  The pencil and paper version is given at most MET sites.  The computer version of the test is given as a "computer adaptive test" (CAT) which means that the test will adapt based on the level of the individual test taker (e.g., if you answer many questions correctly, you may be shown fewer questions).

Including U.S. territories and ships afloat within territorial waters As of 31 December 2009, a total of 1,137,568 personnel were on active duty within the United States and its territories (including 84,461 afloat).[31] The vast majority (941,629 personnel) were stationed at bases within the contiguous United States. There were an additional 37,245 in Hawaii and 20,450 in Alaska while 84,461 were at sea, 2,972 in Guam and 179 in Puerto Rico.

The Electronics Information section of the practice test gauges your knowledge of electrical equipment and parts, including circuits, currents, batteries, and resistors. An example may be, “Because solid state diodes have no filament, they: don’t work, are less efficient than tubes, require less operating power, or require more operating power?” The CAT-ASVAB has 16 questions in 8 minutes; the paper-and-pencil version has 20 questions in 9 minutes.
In exchange for a service commitment, the Reserve Officers' Training Corps (ROTC) program provides you with money for college while you're in school. You must take one military science course along with your other college courses and, upon graduation, enter the service as a commissioned officer. (There is no military commitment for the first year in ROTC, allowing you to pursue ROTC on a trial basis to see if ROTC is for you.) Full ROTC scholarships pay for almost all tuition, fees and books charges for four years of college. ROTC scholarships also come in one, two and three-year lengths. For more information, call 1-800-USA-ROTC (Army), 1-800-USA-NAVY (Navy), 1-866-423-7682 (Air Force) and 1-800-MARINES (Marines).
Auto and Shop Information tests aptitude for automotive maintenance and repair, and wood and metal shop practices. The test covers several areas commonly included in most high school auto and shop courses, such as automotive components, automotive systems, automotive tools, troubleshooting and repair, shop tools, building materials, and building and construction procedures.

Once the ASVAB is over, participants are given a score. This score is used by recruiters to determine which branch of the military would be a good fit for a given test-taker. The most important score for the ASVAB for military purposes is the AFQT score. The AFQT score looks at results from the following sections: Arithmetic Reasoning (AR), Math Knowledge (MK), and multiplies the Verbal Composite (VE) score by two. This is because the Verbal Composite Score is composed of both the Word Knowledge and the Paragraph Comprehension scores. Each branch of the military requires a different minimum AFQT score for its members. For the army and marines, this number is 31, for the navy 35, the air force 36, and the coast guard 45. Therefore, this test is a crucial part of any military career, and can determine potential jobs and advancement opportunities. Along with advancement opportunities come higher salaries and greater benefits, which makes the ASVAB an essential element for prospective military service personnel at any level.
Battlefield commission: under certain conditions, enlisted personnel who have skills that separate them from their peers can become officers by direct commissioning of a commander so authorized to grant them. This type of commission is rarely granted and is reserved only for the most exceptional enlisted personnel; it is done on an ad hoc basis, typically only in wartime. No direct battlefield commissions have been awarded since the Vietnam War. The Navy and Air Force do not employ this commissioning path.
There are many misconceptions about what it’s like to serve in the U.S. military. If you don’t know any soldiers personally, you might think of the military as a place for infantry, trudging though rough terrain and loading giant artillery. Although that may have been true in the past, today’s military offers many opportunities that aren’t readily apparent to the typical high school graduate. For example, there are jobs in aviation mechanics, medicine, and accounting. There are also peacekeeping and humanitarian efforts by the United States military that require skills in verbal and written communication. Taking the exam can help you determine if you would be well-suited to one of these occupations.
The ASVAB is a series of timed aptitude tests that are used to classify selected candidates into appropriate job roles as well as ultimately decide the eligibility of candidates for US military service.  In other words, perform poorly on this test and you could severely limit your opportunities in the military or even prevent yourself from serving.

The President of the United States is the Commander in Chief, who is responsible for all final decisions. The Secretary of the Department of Defense (DoD) has control over the military and each branch - except the Coast Guard, which is under the Dept. of Homeland Security. With over 2 million civilian and military employees, the DoD is the world's largest "company."
In the 2000s, women can serve on U.S. combat ships, including in command roles. They are permitted to serve on submarines.[39] Women can fly military aircraft and make up 2% of all pilots in the U.S. Military. In 2003, Major Kim Campbell was awarded the Distinguished Flying Cross for landing her combat damaged A-10 Thunderbolt II with no hydraulic control and only one functional engine after being struck by hostile fire over Baghdad.