Question: What is the postcode of a town in Cook County, New South Wales, that is situated approximately 100 km west of the Sydney central business district, and about 8 km east of Katoomba?

full_context: Document 1: Blackheath, New South Wales: Blackheath (postcode: 2785) is an Australian town located near the highest point of the Blue Mountains, between Katoomba and Mount Victoria in New South Wales. The town's altitude is about 1065 m   and it is located about 120 km west north-west of the Sydney central business district, 11 km north-west of Katoomba, and about 30 km south-east of Lithgow
Document 2: Cook County, New South Wales: Cook County was one of the original Nineteen Counties in New South Wales and is now one of the 141 Cadastral divisions of New South Wales. It includes the area to the west of Sydney in the Blue Mountains, between the Colo River in the north, and the Coxs River in the south and west, encompassing Lithgow, Mount Victoria, Katoomba, Wentworth Falls, Lawson and most of the other towns in the Blue Mountains. The Nepean River is the border to the east. Before 1834, the area was part of the Westmoreland, Northumberland and Roxburgh counties.
Document 3: Leura, New South Wales: Leura (postcode: 2780) is a suburb in the City of Blue Mountains local government area that is located 100 km west of the Sydney central business district in New South Wales, Australia. It is one of the series of small towns stretched along the Main Western railway line and Great Western Highway that bisects the Blue Mountains National Park. Leura is situated adjacent to Katoomba, the largest centre in the upper mountains, and the two towns merge along Leura's western edge.
Document 4: Cooks River: The Cooks River, a semi-mature tide dominated drowned valley estuary, is a tributary of Botany Bay, located in south-eastern Sydney, New South Wales, Australia.
Document 5: Wentworth Falls, New South Wales: Wentworth Falls (postcode: 2782) is a town in the Blue Mountains region of New South Wales, situated approximately 100 km west of the Sydney central business district, and about 8 km east of Katoomba, Australia on the Great Western Highway, with a Wentworth Falls railway station on the Main Western line. The town is at an elevation of 867 m   . At the 2011 census , Wentworth Falls had a population of .
Document 6: New South Wales: New South Wales (abbreviated as NSW) is a state on the east coast of :Australia. It borders Queensland to the north, Victoria to the south, and South Australia to the west. Its coast borders the Tasman Sea to the east. The Australian Capital Territory is an enclave within the state. New South Wales' state capital is Sydney, which is also Australia's most populous city. In March 2014 , the estimated population of New South Wales was 7.5 million, making it Australia's most populous state. Just under two-thirds of the state's population, 4.67 million, live in the Greater Sydney area. Inhabitants of New South Wales are referred to as "New South Welshmen".
Document 7: Yancowinna County: Yancowinna County is one of the 141 Cadastral divisions of New South Wales. It contains the city of Broken Hill and village of Silverton.
Document 8: Bell, New South Wales: Bell (postcode: 2786) is a small rural and residential village in the Blue Mountains region of New South Wales, Australia. It is the north-westernmost village in the City of Blue Mountains, located approximately 125 km west of Sydney central business district by road or 137 km by rail, approximately 20 km east of Lithgow and 10 km north of Mount Victoria. It is a locality on the junction of the Bells Line of Road, Chifley Road and the Darling Causeway, with an elevation of approximately 1100 m   .
Document 9: South Coast (New South Wales): The South Coast refers to the narrow coastal belt from Sydney in the north to the border with Victoria in the south in the south-eastern part of the State of New South Wales, Australia. It is bordered to the west by the coastal escarpment of the Southern Tablelands, which is largely covered by a series of national parks, namely Jervis Bay National Park, Eurobodalla National Park, and Ben Boyd National Park. To the east is the coastline of the Pacific Ocean, which is characterised by rolling farmlands, small towns and villages along a rocky coastline, interspersed by numerous beaches and lakes.
Document 10: Blue Mountains National Park: The Blue Mountains National Park is a protected national park that is located in the Blue Mountains region of New South Wales, in eastern Australia. The 267954 ha national park is situated approximately 80 km west of Sydney, and the park boundary is quite irregular as it is broken up by roads, urban areas and inholdings. Despite the name 'mountains', the area is an uplifted plateau, dissected by a number of larger rivers. The highest point in the park is Mount Werong at 1215 m above sea level; while the low point is on the Nepean River at 20 m above sea level as it leaves the park.
Document 11: Wentworth, New South Wales: Wentworth is a small border town in the far south west of the state of New South Wales, Australia. It lies at the confluence of Australia's two most important rivers, the Darling and the Murray, the latter forming the border with the state of Victoria to the south. The border with the state of South Australia lies approximately 100 km to the west. The town of Wentworth is in the local government area of the same name.
Document 12: County of Bogong: The County of Bogong is one of the 37 counties of Victoria which are part of the cadastral divisions of Australia, used for land titles. It is located south of the Murray River, east of the Ovens River, and west of the Mitta Mitta River. Mount Bogong is located there, the highest mountain in Victoria.
Document 13: Medlow Bath, New South Wales: Medlow Bath (postcode: 2780) is an Australian small town located near the highest point of the Blue Mountains, between Katoomba and Blackheath. It has an approximate altitude of 1050 m   and is located approximately 115 km west-north-west of the Sydney central business district and 5 km north-west of Katoomba. At the 2011 census, Medlow Bath had a population of 517 people.
Document 14: History of New South Wales: The history of New South Wales refers to the history of the state of New South Wales and the area's preceding Indigenous and British colonial societies. The Mungo Lake remains indicate occupation of parts of the New South Wales area by Indigenous Australians for at least 40,000 years. The English navigator James Cook became the first European to map the coast in 1770 and a First Fleet of British convicts followed to establish a penal colony at Sydney in 1788. The colony established an autonomous Parliamentary democracy from the 1840s and became a state of the Commonwealth of Australia in 1901 following a vote to Federate with the other British colonies of Australia. Through the 20th century, the state was a major destination for an increasingly diverse collection of migrants from many nations. In the 21st century, the state is the most populous in Australia, and its capital, Sydney is a major financial capital and host to international cultural and economic events.
Document 15: City of Blue Mountains: The City of Blue Mountains is a local government area of New South Wales, Australia, governed by the Blue Mountains City Council. The city is located in the Blue Mountains range west of Sydney.
ground_truth: 2782