Please translate and do a gre math problem.

A developer has a piece of land by the river, which is x feet long. The land will be divided into small pieces, each 80 or 100 feet long. If the graph length of 1/9 is 80, and the graph length of 40 is 100, what is x?

Suppose a * * * is divided into n plots, (1- 1/9) n = 45, then n = 45,80 * 5+100 * 40 = 4400.

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