This deep dive covers Conversion Graphs and Cost Graphs within Real-Life Graphs for GCSE Mathematics. Revise Real-Life Graphs in Graphs for GCSE Mathematics with 14 exam-style questions and 12 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 5 of 9 in this topic. Use this deep dive to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 5 of 9
Practice
14 questions
Recall
12 flashcards
Conversion Graphs and Cost Graphs
A conversion graph converts between two units (e.g. miles and kilometres, pounds and euros). It is always a straight line through the origin (0, 0) if there is no fixed charge.
To use a conversion graph:
- Find your value on one axis
- Draw a horizontal (or vertical) line to the graph
- Drop down (or across) to read the converted value
A cost graph may have a fixed charge (y-intercept above zero) plus a rate per unit (gradient).
Example: A gas bill graph passes through (0, 15) and (100, 55).
Fixed charge = £15 (y-intercept)
Rate per unit = (55 − 15) ÷ (100 − 0) = 40 ÷ 100 = £0.40 per unit