Worked Example 3: Percentage Discount vs Multi-Buy
Part of Best Buy — GCSE Mathematics
This study notes covers Worked Example 3: Percentage Discount vs Multi-Buy within Best Buy for GCSE Mathematics. Revise Best Buy in Ratio & Proportion for GCSE Mathematics with 12 exam-style questions and 22 flashcards. This topic appears less often, but it can still be a useful differentiator on mixed-topic papers. It is section 6 of 7 in this topic. Use this study notes to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 6 of 7
Practice
12 questions
Recall
22 flashcards
Worked Example 3: Percentage Discount vs Multi-Buy
Shampoo bottles (300ml each): Normal price £3.50. Offer A: 20% off. Offer B: Buy 2 get 1 free. Which is better for buying 3 bottles?
Step 1 Calculate Offer A (20% discount)
20% off £3.50 = £3.50 × 0.8 = £2.80 per bottle
3 bottles = 3 × £2.80 = £8.40
Price per ml = £8.40 ÷ (3 × 300ml) = £0.0093 per ml
Step 2 Calculate Offer B (buy 2 get 1 free)
Pay for 2 bottles, get 3 bottles
Cost = 2 × £3.50 = £7.00
Price per ml = £7.00 ÷ (3 × 300ml) = £0.0078 per ml
Final Compare offers
£0.0078 per ml < £0.0093 per ml
Buy 2 get 1 free is better value