Let C=no. of Critters on a Stick, F=no. of Corn Fritters, T=no. of Twinkies, D=no. of Mountain Dews in each meal. So total number of each fixin purchased is 500C, 500F, 500T, 500D.
Total number of each fixin bought by x customers is xC, xF, xT, xD.
Leftovers: C(500-x)=465, F(500-x)=T(500-x)=475, D(500-x)=490.
Therefore, 465/C=475/F=475/T=490/D and F=T. So 93/C=95/F=95/T=98/D.
If C=F=T=D=5, 500-x=93 and x=500-93=407 or 405 or 402.
Therefore X=402 and Y=407.