shettyr1 shettyr1 25-02-2021 Social Studies contestada In the U.S. in the 1830s, ________ miles of track had been laid. By the 1860s, ___________ miles of track had been laid. a. 40,000 and 30 b. 30,000 and 30 c. 40 and 30,000 d. 400 and 40,000
