Answer:
air for
is not a pair of equivalent fraction.
Explanation:
Fraction of a ham sandwich left =

Fraction of a turkey sandwich left =

Now we find,
Fraction of sandwich that he eat.
Fraction of a ham sandwich Joseph eat =

Fraction of a Turkey sandwich Joseph eat =

Now the pair of fraction we have are
Pair 1:

Pair 2:

Now, Equivalent fraction are those fractions which has equal simplest form.
Clearly above pair of fractions are already in simplest form.
So, pair 1 of fraction are not equivalent fractions.
Therefore, Pair for
is not a pair of equivalent fraction.