An electricity company charges the same fixed amount for each unit of electricity used - Edexcel - GCSE Maths - Question 9 - 2022 - Paper 3
Question 9
An electricity company charges the same fixed amount for each unit of electricity used.
David uses this graph to work out the total cost of the electricity he has us... show full transcript
Worked Solution & Example Answer:An electricity company charges the same fixed amount for each unit of electricity used - Edexcel - GCSE Maths - Question 9 - 2022 - Paper 3
Step 1
Work out the gradient of the straight line.
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Answer
To find the gradient of a straight line from a graph, we use the formula:
ext{Gradient} = rac{ ext{Change in Cost}}{ ext{Change in Units Used}}
By taking two clear points from the graph, for example, (0, 0) and (100, 20):
Change in Cost = 20 - 0 = 20 £
Change in Units Used = 100 - 0 = 100 units
Plugging these values into the formula gives:
ext{Gradient} = rac{20}{100} = 0.2
Thus, the gradient of the line is 0.2.
Step 2
What does the gradient of this line represent?
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Answer
The gradient of this line represents the cost per unit of electricity. In this case, it indicates that for each unit of electricity used, the cost is £0.20.