Find number abc
If cac69 + 89cc6 = 1a1b05 find number abc. Multiple solutions may exist.Correct answers: 29
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First U.S. traffic tunnel under a riverIn 1866, work began on the first traffic tunnel under a U.S. river, the Washington Street Tunnel in Chicago, Illinois, under the Chicago River. It was built to alleviate traffic congestion at the river's swing bridges and opened 1 Jan 1869. It had a total length of 1,605-ft including approaches. It had a double arch with two roadways 13-ft wide by 11-ft high, and a separate footway on one side 10-ft wide by 10-ft high, reached by stairs. Cable car companies used the tunnel from the 1880's to 1906. To give a deeper draft to the river, it was replaced with a deeper tunnel in 1900, through which electric streetcar service began in 1911-12. The tunnel was closed in 1953. The world's first tunnel under a waterway was the Thames Tunnel, London, opened on 25 Mar 1843.«[Image: Washington Street Tunnel from an undated stereo viewer card.] |