Answer:
It was the same amount the government paid.
Step-by-step explanation:
This is a directly stated, explicit, answer from the text. The text says "The small group of Sioux demonstrators offered to pay the US government $9.40 for the island, or 47 cents per acre- the same amount the government was paying was paying to use tribal lands." This tells us that they thought that it was only fair that since the government wasn't paying them much, that they believed they deserved the same courtesy.