original: if jenny buys a guitar, then she will not buy a keyboard. what is this? if jenny does buy a…

Brief Explanations:

Let (p) be "Jenny buys a guitar" and (q) be "Jenny does not buy a keyboard". The original statement is (p\rightarrow q). The new statement "If Jenny does buy a keyboard, then she will not buy a guitar" is (\neg q\rightarrow\neg p). In logical - statement relationships, the contrapositive of (p\rightarrow q) is (\neg q\rightarrow\neg p).

Answer:

Contrapositive