Macroeconomics 11th Edition by Michael Parkin

Exercise 2

William Gregg owned a mill in South Carolina. In December 1862, he placed a notice in the Edgehill Advertiser announcing his willingness to exchange cloth for food and other items. Here is an extract:
1 yard of cloth for 1 pound of bacon
2 yards of cloth for 1 pound of butter
4 yards of cloth for 1 pound of wool
8 yards of cloth for 1 bushel of salt
a. What is the relative price of butter in terms of wool?
b. If the money price of bacon was 20¢ a pound, what do you predict was the money price of butter
c. If the money price of bacon was 20¢ a pound and the money price of salt was $2.00 a bushel, do you think anyone would accept Mr. Gregg's offer of cloth for salt