Harry drives from Exeter to London in 4 hours at an average speed of 70km/h. Ron drives from Exeter to London in 5 hours. (a) Assuming Ron took the same route as Harry, calculate Ron's average speed.

The distance from Exeter to London can be calculated using the information about Harry's journey. Average speed = Distance/Time so Distance = Average speed x Time. This means that the distance from Exeter to London is 4 x 70km = 280km. Using this answer, the equation can be used again to calculate Ron's average speed. Average speed = 280/5 = 56km/h. There is also a short way to answer this question. Since we know the distance travelled is the same for both journeys, and Ron's journey is 1.25x longer than Harry's (5/4 = 1.25); we can simply divide Harry's average speed by 1.25 to obtain the answer.