Ordering the activity of metals
The activity series summarizes the experimental behavior of metals and their cations. A more active metal will displace the cation of a less reactive metal from solution. 

Let's consider the case of zinc and copper. Zinc is higher on the activity series than copper. Zinc will displace copper ions from solution:

$$\ce{Zn(s) + Cu^2+ (aq) -&gt; Zn^2+ (aq) + Cu(s)}$$

If we place a strip of zinc metal into a solution containing $\ce{Cu^2+}$ ions, the some of the zinc will dissolve into the solution, while some of the copper will plate onto the zinc.

What happens if we put a copper strip into a solution of $\ce{Zn^2+}$? Very little. Copper is less active than zinc. Copper metal will not displace zinc ions from solution.

$$\ce{Cu^2+ (aq) + Zn(s) -&gt; No\ reaction}$$

If you did not know which was more active, copper or zinc, these two experiments would give you the information you need. Zinc displaces copper from solution. Copper does not displace zinc. Zinc is more active than copper $(\ce{Zn&gt;Cu})$.

How can you apply this logic to your question?