[
  "Draw a bar model: Sheila = 1 short bar, Betty = 12 bars of the same length.",
  "12 units = $55.80, so 1 unit = $55.80 ÷ 12 = $4.65 (Sheila).",
  "Total units = 13. Total money = 13 × $4.65 = $60.45."
]