Question

The shortest route from London to Cambridge is 60 miles. A lorry is expected to take 1.5 hours to travel this route. The lorry actually travels by a different route which increases the distance by 20%, but it still arrives in 1.5 hours. By how many more mph than the expected speed does the lorry travel?

Answer 1

Answer: 8 miles per hour

Explanation:

Speed = distance / time

When diatance is 60 miles

Speed = 60 / 1.5 = 40 miles per hour

When distance is 20% more (72 miles)

Speed = 72 / 1.5 = 48 mph