Foundation November 2021 Paper 2 Q23
23 Ali and Badia each have 25 000 dollars to invest.
| Cyclone Bank | Tornado Bank |
|---|---|
| Invest 25 000 dollars 4.5% compound interest per year for 3 years | Invest 25 000 dollars Receive 1150 dollars interest each year for 3 years |
Ali invests in the Cyclone Bank for 3 years.
Badia invests in the Tornado Bank for 3 years.
By the end of the 3 years, Ali will have received more interest than Badia.
How much more?
Show your working clearly.
Give your answer correct to the nearest dollar.
(4)
| Scheme | Marks |
|---|---|
\(\dfrac{4.5}{100} \times 25\,000\ (= 1125)\) or \(\dfrac{104.5}{100} \times 25\,000\ (= 26\,125)\) or 1150 × 3 (= 3450) or 25 000 + 1150 × 3 (= 28 450) (allow \(\dfrac{3 \times 4.5}{100} \times 25\,000\ (= 3375)\) for this mark) | M1 |
\(\dfrac{4.5}{100} \times (25\,000 + \text{‘}1125\text{’})\) (= 1175.625 or 1175 or 1176) and \(\dfrac{4.5}{100} \times (25\,000 + \text{‘}1125\text{’} + \text{‘}1175.625\text{’})\) (= 1228.529) or \(\dfrac{104.5}{100} \times 26\,125\ (= 27\,300.625)\) and \(\dfrac{104.5}{100} \times 27\,300.625\ (= 28\,529.15\ldots)\) | M1 |
| ‘1125’ + ‘1176’ + ‘1229’ (= 3530) or ‘28 529’ – 25 000 (= 3529) and 3 × 1150 (= 3450) or ‘28 529’ and 25 000 + ‘3450’ (= 28 450) | M1 |
| Working required Answer: 79 or 80 | A1 |
| (4) | |
| (4 marks) |
Notes
M1: finding 4.5% or 104.5% of 25 000 (allow for 3 × 0.045 × 25 000 oe) or the total interest for T bank or the total amount gained for T bank
M2 for \(1.045^3 \times 25\,000\) (= 28 529.(15313))
M1: completing the interest for C bank or completing the total amount for C bank
M1: for total interest for C bank and total interest for T bank or total amount for C bank and total amount for T bank
A1: dep on M2
Allow 79 – 80