Higher November 2019 Paper 3 Q6
6
(a) Tom is tiling a wall.
He needs to buy at least 100 tiles.
The tiles are sold in large packs and small packs.
| Large pack 40 tiles £18 Small pack 28 tiles £14 Special offer 25% reduction when you buy 3 or more large packs |
Work out the cheapest cost for Tom to buy the packs of tiles he needs. [3 marks]
(b) Tom is also tiling a floor.
The floor is a rectangle with length 600 cm and width 240 cm
Each tile is a square with side 40 cm
Tom uses this method to work out the number of tiles he needs.
| Number of tiles that will fit along the length Number of tiles that will fit along the width Total number of tiles needed | = 600 ÷ 40 = 15 = 240 ÷ 40 = 6 = 15 + 6 = 21 |
Give a reason why Tom’s method is wrong. [1 mark]
| Answer | Mark | Comments |
|---|---|---|
| \(3 \times 18\) or 54 or \(2 \times 18 + 14\) or 50 or \(18 + 3 \times 14\) or 60 or \(4 \times 14\) or 56 or \(1 - 0.25\) or 0.75 seen | M1 | oe |
| \(3 \times 18 \times (1 - 0.25)\) or \(3 \times 18 \times 0.75\) or 40.5 or \(18 \times (1 - 0.25)\) or \(18 \times 0.75\) or 13.5(0) | M1dep | oe |
| 40.50 | A1 | condone £40.50p |
Additional guidance
| 40.5 on answer line | M1M1A0 |
| Answer | Mark | Comments |
|---|---|---|
| Should have multiplied 15 by 6 or 90 | B1 | oe eg \(15 \times 6\) accept \(\dfrac{240 \times 600}{40 \times 40}\) or \(\dfrac{144\,000}{1600}\) |
Additional guidance
| Ignore irrelevant statements alongside a correct answer | |
| \(15 \times 6\) seen but evaluated incorrectly | B1 |
| Should have multiplied not added | B1 |
| Should have multiplied at the end | B1 |
| Adding was wrong | B1 |
| He has added | B1 |
| Times the number for length and width | B1 |
| Times the length and width | B0 |
| Calculation at the end is wrong | B0 |
| Should have multiplied | B0 |
| Needs to work out the area | B0 |
| 21 is wrong | B0 |
| Answer is wrong | B0 |