Question

Every 3rd car has a number. Every 4th car has a stripe. Which of the cars below would have both a number and a stripe? A 18th B 28th C 40th D 48th

Answer 1

Every 3rd car has a number:

$\lbrace3,6,9,12,15,18,21,24,27,30,33,36,39,42,45,48,\ldots\rbrace$

Every 4th car has a stripe:

$\lbrace4,8,12,16,20,24,28,32,36,40,44,48,\ldots\rbrace$As you can see the cat that has a number and a stripe is car 48th