Question: How old do you have to be to buy a handgun in the state where Knoxville Raceway is located?

full_context: Document 1: Gun laws in Michigan: At the age of 18 or up, it is legal to buy a pistol with a purchase license from a private seller, at the age of 21, it is legal to buy a firearm from a Federally licensed (FFL) dealer. No purchase license is required to purchase a long gun (a firearm that is more than 26 inches long) in Michigan. According to state law, a long gun may be purchased by anyone aged 18 or over who is not subject to restrictions based on criminal history, mental health history, or other disqualifying factor. A person must be at least 18 years old to purchase a long gun from a federal dealer or a private seller under Michigan law.
Document 2: Knoxville Raceway: Knoxville Raceway is a semi-banked 1/2 mile dirt oval raceway (zook clay) located at the Marion County Fairgrounds in Knoxville, Iowa, United States. Races at the "Sprint Car Capital of the World" are held on Saturday nights from April through September each year. Some special events may start as early as Wednesday and build up to Saturday. Regular events include 305 cubic inch, 360 cubic inch and 410 cubic inch sprint car racing. Each August, the Raceway holds the paramount sprint car event in the United States, the Knoxville Nationals. The track is governed by the 24-member fair board elected by Marion County residents.
Document 3: Gun laws in Arizona: Arizona gun laws are found mostly in Title 13, Chapter 31 of the Arizona Revised Statutes. There is no registration or licensing of non-NFA firearms in Arizona. Section 13 - 3108 subsection B prohibits any political subdivision of the state from enacting any laws requiring licensing or registration. According to state law, a person must be 18 years of age to purchase any non-NFA firearm from any source; however, there is a federal age limit of 21 years on handgun purchases from federal firearms licensees.
Document 4: Gun laws in Iowa: A Permit To Acquire (PTA), obtained from the sheriff of the county of the applicant's residence, is required when purchasing or otherwise acquiring a handgun, either from a dealer or from a private party. A Permit To Acquire shall be issued to qualified applicants aged 21 or older. The PTA becomes valid three days after the date of application, and is valid for one year. A PTA is not required when purchasing an antique handgun, defined as one made in or before 1898 and including post-1898 replicas of matchlock, flintlock, or percussion cap pistols.
Document 5: Beaver Dam Raceway: Beaver Dam Raceway is a one-third mile banked clay oval track located in Beaver Dam, Wisconsin, U.S.A.. The track holds weekly races over the Northern American summer months. It hosts an annual World of Outlaws sprint car races. The 2013 U.S. Dirt Legends Nationals event was held at the track.
Document 6: Gun laws in Indiana: Indiana is a ``shall issue ''state for the License To Carry a Handgun. A license to carry will be issued to individuals age 18 or older who meet a number of legal requirements. Currently both limited term and unlimited lifetime licenses are available.
Document 7: Potomac Speedway: Potomac Speedway is a 3/8 mile clay oval raceway located in Budds Creek, Maryland, near Charlotte Hall. The raceway was first raced on in 1973. Races are typically held on Friday or Saturday nights. Regular events include Super Late Models, Limited Late Models, Street Stocks, and Hobby Stocks and 4 cylinders. The speedway also holds events for Modifieds, Crate Late Models, Strictly Stocks and Hornets. Potomac Speedway has a seating capacity of about 4,000 in the main grandstands and can hold an additional 1,000 in the pit area.
Document 8: Oklahoma City: Other major sporting events include Thoroughbred and Quarter horse racing circuits at Remington Park and numerous horse shows and equine events that take place at the state fairgrounds each year. There are numerous golf courses and country clubs spread around the city.
Document 9: Gun laws in Washington: As a general rule, a person may legally open - carry in Washington state in any place it is legal to possess a loaded handgun, as long as it does not manifest ``an intent to intimidate another or (warrant) alarm for the safety of other persons. ''To open - carry a handgun in a vehicle (e.g, car, bus, etc...) a person must have a valid concealed pistol license. The county sheriff or city police chief shall issue a concealed pistol license to any applicant, age 21 or older, who meets certain requirements, including no felony convictions, no misdemeanor domestic violence convictions, and no outstanding warrants. Open carrying of firearms is not prohibited by law, although trouble with some law enforcement agencies has been encountered while open carrying in the past, most notably in a case in Ellensburg, Washington.
Document 10: Bristol Motor Speedway: Bristol Motor Speedway, formerly known as Bristol International Raceway and Bristol Raceway, is a NASCAR short track venue located in Bristol, Tennessee. Constructed in 1960, it held its first NASCAR race on July 30, 1961. Despite its short length, Bristol is among the most popular tracks on the NASCAR schedule because of its distinct features, which include extraordinarily steep banking, an all concrete surface, two pit roads, and stadium - like seating. It has also been named one of the loudest NASCAR tracks.
Document 11: Gun laws in Tennessee: A license is required to carry a loaded handgun either openly or concealed. Such permits are issued through the Department of Safety to qualified residents 21 years or 18 years old if the applicant is active duty, reservist, guardsman, or honorably discharged from their branch of service, DD - 214 must mention 'pistol qualification' in order to be exempt from 8 hour safety course must have a valid military ID. The length of the term for the initial license is determined by the age of the applicant. If renewed properly and on time, the license is renewed every 5 years. Tennessee recognizes any valid, out - of - state permit for carrying a handgun as long as the permittee is not a resident of Tennessee. Nonresidents are not issued permits unless they are regularly employed in the state. Such persons are then required to obtain Tennessee permits even if they have home state permits unless their home state has entered into a reciprocity agreement with Tennessee. Permittees may carry handguns in most areas except civic centers, public recreation buildings and colleges. Businesses or landowners posting ``no carry ''signs may prohibit gun carry on any portion of their properties.
Document 12: Exhibition game: Various auto racing organizations hold exhibition events; these events usually award no championship points to participants, but they do offer prize money to participants. The NASCAR Sprint Cup Series holds two exhibition events annually - the Sprint Unlimited, held at Daytona International Speedway at the start of the season, and the NASCAR Sprint All-Star Race, held at Charlotte Motor Speedway midway through the season. Both events carry a hefty purse of over USD $1,000,000. NASCAR has also held exhibition races at Suzuka Circuit and Twin Ring Motegi in Japan and Calder Park Thunderdome in Australia.
Document 13: Tucson, Arizona: Tracks include Tucson Raceway Park and Rillito Downs. Tucson Raceway Park hosts NASCAR-sanctioned auto racing events and is one of only two asphalt short tracks in Arizona. Rillito Downs is an in-town destination on weekends in January and February each year. This historic track held the first organized quarter horse races in the world, and they are still racing there. The racetrack is threatened by development. The Moltacqua racetrack, was another historic horse racetrack located on what is now Sabino Canyon Road and Vactor Ranch Trail, but it no longer exists.
Document 14: Cornwall Motor Speedway: The Cornwall Motor Speedway is a 1/4 mile dirt track near the community of Cornwall, Ontario, Canada. It is located northwest of the city on Cornwall Centre Road. The track opened in 1970 and runs weekly racing on Sunday evenings.
Document 15: Gun laws in Ohio: In April 2004, Ohio became the 46th state to legalize concealed carry and its statute went into effect. The law (Ohio Revised Code (O.R.C.) 2923.12, et seq.) allows persons 21 and older to receive a concealed handgun license provided that they receive a minimum of 8 hours of handgun training (6 hours of classroom instruction and 2 hours of range time) from a certified instructor, demonstrate competency with a handgun through written and shooting tests, pass a criminal background check, and meet certain residency requirements (non-residents who work in Ohio will be allowed to obtain licenses as of March 23, 2015).
ground_truth: 21 or older.
sub_queries: In which state is Knoxville Raceway located? Answer: Iowa
how old do you have to be to buy a handgun in Iowa Answer: 21 or older.