Hint
Use the stated units and precision. Use the gradient of the outward journey.
Worked solution
(a)
Use the gradient of the outward journey.
\(5\) is outward distance divided by outward time.
Answer: \(5\)
(b)
Add both journey lengths, rather than the final distance from home.
The outward and return legs are each 10 km, giving 20 km.
Answer: \(20\)
(c)
Include both journeys and the stop in elapsed time.
Travel and waiting times add to 8 h.
Answer: \(8\)
Maths4U indicative marking guidance
Maths4U indicative marking guidance, not an official mark scheme. Credit complete valid alternative methods and consequential reasoning. An unexplained result does not earn a method mark.
(a) · 2 marks
- 1 mark: Use the gradient of the outward journey.
- 1 mark: Give the correct requested result, retaining signs, units and any domain restrictions.
Alternative methods: Any complete mathematically valid alternative method with the same restrictions and equivalent exact result is acceptable.
Common error: Keep intermediate values exact until the final step.
(b) · 2 marks
- 1 mark: Add both journey lengths, rather than the final distance from home.
- 1 mark: Give the correct requested result, retaining signs, units and any domain restrictions.
Alternative methods: Any complete mathematically valid alternative method with the same restrictions and equivalent exact result is acceptable.
Common error: Check the answer against the original conditions.
(c) · 2 marks
- 1 mark: Include both journeys and the stop in elapsed time.
- 1 mark: Give the correct requested result, retaining signs, units and any domain restrictions.
Alternative methods: Any complete mathematically valid alternative method with the same restrictions and equivalent exact result is acceptable.
Common error: Keep intermediate values exact until the final step.
Total: 6 marks.