The answer
the card pictures are scaled in two dimensions, so area exaggerates the increase
O-Level E-Math 2019 Paper 1 Question 2 · Verified worked solution by the Genius Plus Academy teaching team
What this question tests
This is Question 2 of the O-Level E-Math 2019 Paper 1. It tests misleading diagrams (area vs length), in the Data handling / misleading statistics area. It is worth 1 mark. It is a worded / diagram-based question, so open your Ten-Year Series (TYS) or the official paper at this question, then follow our full worked solution below.
Each year's value is drawn as a picture of a credit card that is enlarged in both width and height. Because the area of the picture grows roughly as the square of the linear scaling, the images make the increase in spending look much larger than it actually is (the eye compares the areas of the cards, not their heights). A fair chart would use bars of equal width whose heights alone represent the values.
Answer: the card pictures are scaled in two dimensions, so area exaggerates the increase
Same structure, different numbers
Swap the constants, dress a quadratic as a length, hide a derivative inside an integral, and a student sees a brand new problem. The structure underneath is the same, and so is the method. Once a student can name the structure, a whole row of questions that look different start to open the same way.
That is where marks really leak: in choosing the method, not in the algebra that follows. We call it Lock and Key, name the lock, then the key follows.
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Genius Plus Academy · O-Level & IP Mathematics
Our O-Level E-Math tuition trains the same recognise-the-structure method these worked solutions show, taught by a team that has marked these papers for years. It runs within our weekly Secondary Math programme, Sec 1 to 4 and IP.
It is a misleading diagrams (area vs length) question from Data handling / misleading statistics, worth 1 mark.
Yes. IP (Integrated Programme) schools teach the same O-Level Mathematics content; they just sequence it differently and set their own internal exams, so these worked solutions apply to IP students too.
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