Foundation November 2021 Paper 1 Q18
18 The cost of making a phone call is
a fixed charge
and
a charge per minute.
The costs of phone calls up to 5 minutes are represented by the graph.
(a) Write down the fixed charge. [1 mark]
(b) Work out the charge per minute. [2 marks]
(c) Work out the cost of a phone call lasting 7 minutes. [2 marks]
| Answer | Mark | Comments |
|---|---|---|
| 20 | B1 |
| Answer | Mark | Comments |
|---|---|---|
| \(28 - 20\) or \(\dfrac{36 - 20}{2}\) or \(\dfrac{44 - 20}{3}\) or \(\dfrac{52 - 20}{4}\) or \(\dfrac{60 - 20}{5}\) or correct calculation using any two points, eg \(\dfrac{60 - 44}{2}\) or \(2 \times 4\) | M1 | |
| 8 | A1 |
Additional guidance
| \((60 \div 5 =)\ 12\) | M0A0 |
| Answer | Mark | Comments |
|---|---|---|
| Alternative method 1 | ||
| their \(20 + 7 \times\) their 8 | M1 | oe |
| 76 | A1ft | correct answer or ft their values in (a) and (b) |
| Alternative method 2 | ||
| \(60 + 2 \times\) their 8 | M1 | oe |
| 76 | A1ft | correct answer or ft their values in (b) |
Additional guidance
For Alt 2, they may read off any cost for \(n\) minutes (from 1 to 5) and add on \((7 - n) \times\) their (b) for M1. A1 or A1ft may follow from their working