As is often the case, here only one pair of ions is insoluble together. The other two ions are known as "spectators" and remain unchanged. The only way to recover the compound they might form is to remove the water.
What should we expect to happen to the conductivity of such a mixture? What would we expect to happen if both products were insoluble (i.e., precipitated)?
There is so much data from the lab that before we can use it to write correct reactions we need to reduce it a litttle and organize it. One helpful piece of information is that no combination of ions including either NH4+ or NO3- formed a precipitate. Apparently all such compounds are water-soluble. This is indicated in the table that follows.