Why was the united states willing to pay more per mile for the gadsden purchase than for the mexican cession?

The Gadsden Purchase gave the United States land to build a railroad.

Explanation:

The United States was willing to pay more money for the Gadsden Purchase than for the Mexican Cession because this purchase allowed them to have more land in order to build the railroad. Moreover, it allowed the United States to continue its plans of conquering all of North America. The treaty was ratified on April 25, 1854, and it purchased 29,670 square miles of land, paying Mexico $10 million.

yup! you are correct it is b.

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