It is seems obvious that if you increase the REACTANT ONLY, the position of Equilibrium will move to the product side. Thus making more product if you measured it again in the second equilibrium. HOWEVER, what will happened if you increase BOTH of the product and reactant?
If you increase the amount of product and reactant in the proportions that they exist in, at equilibrium, then nothing will happen. It would be as if you had two flasks of reactants at equilibrium and connected them together.
If the product and reactant were not added in their equilibrium proportions then the reaction would convert one into the other until they were at their equilibrium proportions.
This assumes that it is a closed system etc.