Not sure if this is possible: If a, b, c, f are 4 nonzero nu

[degreeplus]

If a, b, c, and f are four nonzero numbers, then all of the following proportions are equivalent EXCEPT

(A) a/f=b/c
(B) f/c=b/a
(C) c/a=f/b
(D) a/c=b/f
(E) af/bc=1/1

The answer should be (A).
This is all that is given. If the variables only have the requirement of not being zero can they not be any number then? Is there anyway to solve this?

 

[skeeter]

choices (B) thru (E) all say the same thing, af = bc ... cross multiply each one to see what I mean.

 

[degreeplus]

hmm didnt notice that, but.. is it accurate to say that the proportions are equivalent?

 

[skeeter]

yes, the proportions given in choices (B) thru (E) are all equivalent.