4MA0 Higher June 2017 Paper 3R Q10
10 The price of 1 kg of silver on 1st January 2010 was $607
By 1st January 2015, the price of 1 kg of silver had decreased by 9.4%
(a) Work out the price of 1 kg of silver on 1st January 2015.
Give your answer correct to the nearest dollar ($). (3)
Give your answer correct to the nearest dollar ($). (3)
Between 1st January 2010 and 1st January 2015, the price of 1 tonne of copper decreased by 20%
This was a decrease of $1320
(b) Work out the price of 1 tonne of copper on 1st January 2010. (3)
| Scheme | Marks |
|---|---|
100 − 9.4 (= 90.6) or \(\dfrac{9.4}{100} \times 607\) oe (= 57.058) | M1 |
\(\dfrac{\text{“}90.6\text{”}}{100} \times 607\) oe or 607 – “57.058” | M1 |
| 550 | A1 |
| (3) |
Notes
M1: (dep)
A1: for 549.942 or 549.94 or 549.9
| Scheme | Marks |
|---|---|
| \(\dfrac{100}{20} \times 1320\) oe | M2 |
| 6600 | A1 |
| (3) | |
| (6 marks) |
Notes
M2: for a complete method
If not M2 then award M1 for a correct first step
1320 ÷ 20 (=66) or \(0.2x = 1320\) or
1320 ÷ 2 (=660)