Answer
Nikolai Ryzhkov succeeded Nikolai Tikhonov as Chairman of the Council of Ministers, a position he held from 1985 to 1990. Tikhonov was appointed as Chairman of the Council of Ministers in 1980, following the death of Leonid Brezhnev. He was succeeded by Ryzhkov in 1985, after Mikhail Gorbachev became General Secretary of the Communist Party of the Soviet Union.