Foundation November 2019 Paper 3 Q18
18
(a) Write down the multiplier for an increase of 140%.
Give your answer as a decimal. [1]
Give your answer as a decimal. [1]
(b) Ali invests £1500 in October.
The investment increases in value by 10% in November.
It then decreases in value by 20% in December.
The investment increases in value by 10% in November.
It then decreases in value by 20% in December.
Ali says
10% – 20% = –10%, so the £1500 has lost exactly 10% of its value.
(i) Explain what Ali has done wrong. [1]
(ii) Work out the correct percentage loss. [5]
| Answer | Marks | Part marks and guidance | |
|---|---|---|---|
| 2.4 | 1 | ||
| Answer | Marks | Part marks and guidance | |
|---|---|---|---|
| (i) Percentages are not of the same amount oe | 1 | If calculation used 10% of 1500 = 150 80% of 1650 = 1320 1500 – 150 = 1350 It has lost more [than 10%] | If calculation, must contain all four steps Accept anything that suggests 20% is of a different amount [than 1500] |
| (ii) 12 nfww | 5 | M3 for \(1500 \times \left(1 - \left(1 + \dfrac{10}{100}\right)\left(1 - \dfrac{20}{100}\right)\right)\) oe possibly implied by 180 or M2 for \(1500 \times \left(1 + \dfrac{10}{100}\right) \times \left(1 - \dfrac{20}{100}\right)\) oe possibly implied by 1320 or M1 for \(\times \left(1 + \dfrac{10}{100}\right)\) oe possibly implied by 1650 AND M1 for \(\dfrac{\textit{their } 180}{1500}\) [× 100] oe | If non calculator methods, must show operations to score method marks M3 for 1500 × (1 – 1.1 × 0.8) May be in stages e.g 1500 ÷ 10 = 150 M1 1500 + 150 = 1650 1650 ÷ 10 × 2 = 330 M2 1650 – 330 = 1320 M3 1500 – 1320 = 180 M1 180 ÷ 1500 × 100 = 12 ALTERNATIVE not using 1500 B1 for 1.1 or 110% B1 for 0.8 or 80% M1 for 1.1 × 0.8 soi 0.88 M1 for (1 – their 0.88) × 100 |