[
  "Find the original number of boys and girls by dividing the new numbers by 1.10 and 1.04.",
  "Original boys = 121 / 1.10 = 110. Original girls = 156 / 1.04 = 150.",
  "Total increase = 277 - 260 = 17. Percentage = 17/260 * 100% = 6 7/13 %."
]