Number 9
4 marks · NormalA coffee shop sells hot chocolate in three cup sizes:
| Size | Volume (ml) | Price ($) |
|---|---|---|
| Small | 180 | 2.40 |
| Medium | 240 | 3.20 |
| Large | 350 | 4.90 |
Work out, giving your answers to 2 decimal places, which cup size gives the best value for money. Show all your calculations.
Calculate the price per 100 ml for each cup size.
Which cup size offers the best value for money?
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
(a) —
(b) Large cup
Common mistakes: Comparing only total price, not unit price.
Show mark scheme and worked solution
Marking points
M1 (a) · 1 mark · Attempt to find price per 100 ml for one or more cups.
A1 (a) · 1 mark · Correctly calculate price per 100 ml for all three sizes (to 2 decimal places). (follow-through)
M2 (b) · 1 mark · Correctly identify the best value cup from their own calculations. (follow-through)
B1 (b) · 1 mark · State the correct cup size (large) as the best value for money. (follow-through)
Worked solution
| Size | Calculation | Price per 100 ml ($) |
|---|---|---|
| Small | 2.40 ÷ 180 × 100 | 1.33 |
| Medium | 3.20 ÷ 240 × 100 | 1.33 |
| Large | 4.90 ÷ 350 × 100 | 1.40 |
Small and medium cups both cost $1.33 per 100 ml, large is $1.40 per 100 ml. Best value is the small or medium cup.