GCSE · Compound units & rates

Speed, distance and timeExam-style questions

Why speed is a rate (distance per one unit of time), how the three formulas are one relationship, why time must be in decimal hours, and why average speed is total distance over total time — never the mean of the speeds.

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14 questions · GCSE (Higher) level · mark scheme and worked solution on each · no sign-up to try

DifficultyAll Level 1 Level 2 Level 3 Level 4 Level 5

1
Amir drives 120 km at an average speed of 60 km/h, and then a further 120 km at an average speed of 40 km/h.

Meera says: "The average speed for the whole journey is 50 km/h, because the mean of 60 and 40 is 50."

(a) Show that the whole journey takes 5 hours.

(b) Work out the average speed for the whole journey, and explain why Meera is wrong.
Level 5 · 5 marksTry it
2
Two trains are $180$ km apart on the same line and travel towards each other, one at $70$ km/h and the other at $50$ km/h.

(a) Work out how long it takes until they meet. Give your answer in hours and minutes.

(b) Work out how far the faster train travels before they meet.
Level 5 · 5 marksTry it