Numeracy Higher November 2017 Unit 2 Q5
5. Teleri needs £8000 to pay a deposit for a new house.
She already has £7500.
Teleri decides to invest the £7500 in a bank account that pays interest at a rate of 0·31% every month.
She does not plan to make any further payments into this account.
Calculate the number of months Teleri will need to wait until she has enough money in the account to pay the deposit of £8000. [3]
| Scheme | Marks | Comments |
|---|---|---|
| \(7500 \times 1{\cdot}0031^n\) | B1 | For any value of n (7500 × 1·0031 = (£)7523.25) May be implied |
| \(7500 \times 1{\cdot}0031^{21}\) (= (£) 8003.68(7105)) | M1 | Allow \(7500 \times 1{\cdot}0031^{20}\) (=(£) 7978.95(2352)) with convincing work that (£) 8000 will be reached the following month. |
| 21 (months) | A1 | Answer clearly seen, not embedded in their method. |