[
  "Let Pass = 7k, Fail = 3k, Total = 10k. After 24 more pass, pass = 7k + 24.",
  "New pass rate: (7k + 24) / 10k = 0.85.",
  "Cross multiply: 7k + 24 = 8.5k. Solve: k = 16. Total = 160."
]