the key idea here is that we can't have half a pack (the store owner would be really angry if you cut the packs!). therefore we are really finding the least common multiple of 14 and 5. to find lcm is really hard to explain with the limited technology on this website. i highly recommend you search up ladder method online. i can, however, tell you that the lcm of 14 and 5 is 70 so 70 is the minimum NUMBER of markers (not packs) that blaaine would have to buy.