Suppose that hot dogs come in packs of 6 and buns come in packs of 10. Rafael bought the same number of hot dogs as buns. It was the least number of each for which this was possible.
I suppose you are wondering the least number of each (buns and dogs packages) to have the same number of each :buns = dogs
LCM of 10 and 6 is 30 so Raf would buy 5 packs of hot dogs and 3 packs of buns.