Marking logic
For 9709/42 Q5 (8 marks), credit is awarded for examiner-visible method and a correct finish on syllabus point 4.1. Typical split: early method marks for a valid approach, later accuracy marks for the demanded quantity (with units/significant figures where the scheme requires them). Silent final answers usually forfeit method credit.
Step-by-step expected reasoning
Mark against the official 9709 scheme for this paper/session: tick only what the scheme awards, then note which mark point failed. That failure map is the study plan — not a vague “revise the chapter.”
Where students lose marks
- Skipping the defining equation or first method line before substituting numbers.
- Using the wrong command-word depth (e.g. “state” vs “explain”).
- Losing the final accuracy mark through rounding, units, or significant figures.
- Answering a related quantity instead of the one the stem asked for.
Alternative valid approaches
Where the scheme allows equivalent methods, any valid approach that reaches the same demanded result can still earn method marks. Do not force one textbook route if your working is mathematically equivalent and examiner-readable.
Targeted remediation
Close the gap on syllabus point 4.1 with the linked lesson, then re-mark a fresh attempt. The win condition is earning the previously missed mark points — not rereading notes without another timed try.