The scale diagram below shows two cities, P and Q - OCR - GCSE Maths - Question 5 - 2018 - Paper 1

To find the average speed of the plane, we first need to determine the distance and time.

1. Calculate the distance:

   • Measure the distance between cities P and Q in cm from the diagram. Assume it measures 'd' cm.

   • Using the scale, convert this distance to kilometers: $ext{Distance (km)} = d imes 125$

2. Calculate the time taken:

   • Departure time: 09:47

   • Arrival time: 12:07

   • To find the duration in hours, first convert both times to minutes:

     Departure: 9 hours and 47 minutes = 9 * 60 + 47 = 587 minutes Arrival: 12 hours and 7 minutes = 12 * 60 + 7 = 727 minutes

   • Calculate the total time taken: $ext{Time (minutes)} = 727 - 587 = 140 ext{ minutes}$ ext{Time (hours)} = rac{140}{60} ext{ hours}

3. Calculate the average speed:

   • Using the formula for average speed: ext{Average Speed (km/h)} = rac{ ext{Distance (km)}}{ ext{Time (hours)}}

   • Thus, substituting the values gives: ext{Average Speed} = rac{d imes 125}{rac{140}{60}}

   • Further simplify to find the average speed in km/h.