question: How far from Nanjing is the Yangshan Quarry ?
answer: 15 -- 20 km ( 9 -- 12 mi ) east of the walled city
turker_answer: The Yangshan is Quarry 15-20 km ( 9-12 mi ) east of the walled city .
rule-based: The Yangshan is Quarry 15 -- 20 km ( 9 -- 12 mi ) east of the walled city .