[ZenGum]

"all sold their corn at the same prices" ... same price per bushel or same price for a year's production of corn regardless of volume?

"each received the same amount of money for his corn" ... same as each other, or the same meaning "same as previously mentioned".

Either of these allows a solution.

Or it could be that A really sucks at business and/or maths.

Or they're running a co-op. Damn commies.