Playbook
Percentage, Profit and Loss
50 q · 6% HARD · about 2.4 a paper — three HARD questions in the whole chapter. The only way to lose a mark is the wrong base.
- Questions in the bank
- 50
- q/paper (21 papers)
- 2.38
- Tagged HARD
- 6%
- Subtopics
- 4
Strand: Quick-Win
When you’ll see it
A percentage, a profit or loss, a discount, or two changes one after another.
How this chapter is tested
50 questions, about 2.4 a paper, and only three HARD questions in the chapter. The one way to lose marks here is taking a percentage of the wrong base.
The sub-skills
The distinct skills inside the chapter, in the order to learn them.
Percentage of a base
x% more than y is y(1 + x/100); y is then less than x by x/(100 + x) × 100%.
Successive change
Changes of a% and b% combine to a + b + ab/100.
Profit and loss
On cost price; selling price = CP × (1 + p/100).
Discount
On marked price; successive discounts multiply.
Traps to expect
Distractor shapes this chapter reuses. The Traps page covers the ones that cut across chapters.
The wrong base
A 20% rise followed by a 20% fall is a 4% fall, not zero.
Profit on selling price
Profit % is on cost unless the question says otherwise.
Learn it before you drill it
This chapter has full teaching notes — foundations, worked examples, self-checks and a mastery check for each subtopic. Read the notes once, then drill subtopic by subtopic below.
Percentage, Profit and Loss notesDrill every Percentage, Profit and Loss question
50 questions from the bank, across 4 subtopics.
Drill one subtopic at a time
The 4 subtopics, in teaching order.
- PercentageDrill Percentage
- Successive Percentage ChangeDrill Successive Percentage Change
- Profit and LossDrill Profit and Loss
- Successive Discount and Marked PriceDrill Successive Discount and Marked Price
Related playbooks
Often paired with this one — the technique or the trap overlaps. Drill these next.