1MA0 Higher June 2012 Paper 2 Q15
*15 Henry is thinking about having a water meter.
These are the two ways he can pay for the water he uses.
| Water Meter | No Water Meter |
|---|---|
| A charge of £28.20 per year plus 91.22p for every cubic metre of water used 1 cubic metre = 1000 litres | A charge of £107 per year |
Henry uses an average of 180 litres of water each day.
Henry wants to pay as little as possible for the water he uses.
Should Henry have a water meter? (5)
| Working | Answer | Mark | Notes |
|---|---|---|---|
| 180 × 365 =65700 65700 ÷1000 =65.7 65.7 × 91.22 =5993.154 5993.154÷100 + 28.20 =88.13... (see the table below) | Decision (Should have a water meter installed) | 5 | Per year M1 for 180 × ‘365’ (= 65700) M1 for ‘65700’ ÷ 1000 (= 65.7 or 65 or 66) M1 for ‘65.7’ × 91.22 (= 5993...) A1 for answer in range (£)87 to (£)89 C1 (dep on at least M1) for conclusion following from working seen OR (per day) M1 for 107 ÷ ‘365’ (= 0.293…) M1 for 180 ÷ 1000 × 91.22 (= 16.4196) M1 for 28.2 ÷ ‘365’ + ‘0.164196’ (units must be consistent) A1 for 29 – 30(p) and 24 – 24.3(p) oe C1 (dep on at least M1) for conclusion following from working seen OR M1 for (107 – 28.20) ÷ 0.9122 (= 86.384..) M1 for ‘86.384..’× 1000 (= 86384.5…) M1 for ‘365’ × 180 (= 65700) A1 for 65700 and 86384.5... C1 (dep on at least M1) for conclusion following from working seen NB : Allow 365 or 366 or 52×7 (=364) or 12 × 30 (=360) or 365¼ for number of days |
Working table from the mark scheme
