[
  "Make the common term Adults the same number of units in both ratios to form a three-way ratio.",
  "Adults : Girls = 5 : 2 = 10 : 4. So Adults : Boys : Girls = 10 : 1 : 4. 10 units = 250 adults, so 1 unit = 25.",
  "Total = 250 + (1x25) + (4x25) = 250 + 25 + 100 = 375 people."
]