This is merely a stoiciometry exercise, somewhat generalized. Find which reactant is the limiting reactant; that determines how much of the other reactant will be consumed.
The written reaction shows 1 mole of X; the situation uses 3 moles of X.
The written reaction shows 5 moles of Y; the situation uses 2.8 moles of Y.
Either X or Y is likely to be in excess. Which one? The other is then the limiting reactant.