A train travelled along a track in 110 minutes, correct to the nearest 5 minutes - Edexcel - GCSE Maths - Question 17 - 2017 - Paper 3

The fact that Jake assumed the track length was measured to the nearest 10 km influences the conclusions drawn in part (a). If the track's actual length is 270 km correct to the nearest 5 km, this means the possible actual length could range from:

• Minimum length: 270 - 2.5 = 267.5 km
• Maximum length: 270 + 2.5 = 272.5 km

This shorter distance means, in the same time period of 110 minutes, the average speed would be lower than previously calculated.

By calculating based on the correct measurement, it shows that:

1. Minimum Average Speed: Using the minimum length (267.5 km):

   $\text{Average Speed} = \frac{267.5 \text{ km}}{\frac{11}{6} \text{ hours}} \approx 146.6 \text{ km/h}$

This confirms that, considering the track's actual measurement accuracy, it further proves that the average speed of the train can’t exceed 160 km/h, supporting the conclusion from part (a).