Every 3rd car has a number:
[tex]\lbrace3,6,9,12,15,18,21,24,27,30,33,36,39,42,45,48,\ldots\rbrace[/tex]
Every 4th car has a stripe:
[tex]\lbrace4,8,12,16,20,24,28,32,36,40,44,48,\ldots\rbrace[/tex]As you can see the cat that has a number and a stripe is car 48th
