[
  "Draw a bar model: divide 135 into 3 equal parts. Relatives get 1 part. Then split the remaining 2 parts into 6 equal sub-parts; friends get 1 sub-part.",
  "Relatives: 1/3 x 135 = 45 tickets. Remainder = 135 - 45 = 90. Friends: 1/6 x 90 = 15 tickets.",
  "Difference = 45 - 15 = 30. Answer: 30."
]