I have an old Japanese textbook from college that I'm going back over to brush up on what I know already. In one section, which teaches basic comparisons, they show a picture of a shinkansen, a densha and a basu. The first question asks which of those is the slowest, so I wrote "Basu ga ichiban osoi desu."
Now, the next question asks which is the cheapest, and the answer is, again, the bus. In this particular instance, is it correct to write "Basu mo ichiban yasui desu" to indicate that it is the cheapest as well as the slowest? It strikes me as not being right, but I'm not confident about it at all. Any ideas?
Thanks in advance.