Find the total distance for each group, then the overall average.<br><br>&bull; Total for 31 pupils = 134 × 31 = 4154 cm<br>&bull; Total for 4 pupils = 125.25 × 4 = 501 cm<br>&bull; Total for all 35 pupils = 4154 + 501 = 4655 cm<br>&bull; New average = 4655 ÷ 35 = 133 cm<br><br>Final Answer: 133 cm