S1 (Viva Voce) Part B Reflection
This question reminds me of question back in the past when we were primary schools where models were used as the method.
It just like a question that asks you how much a pear cost if a person brought 5 pears and have $1.50 left and if brought 6 the person would be short of $(n). (I would use this question as a comparison to the original question)
This question is asking us to find the value of x and x is a VARIABLE, which means it can be of any value unless we found out what it is. Just like the cost of a pear.
Since the lengths of the ABCD rectangle are the same, their total value after calculating must be the same. This is the constant value, just like how much the person has when he/she is buying pears.
To solve this question, the final two model must be of the same length. We know that if there is too much of x, we need to minus of a certain value and if too less, we need to add a certain value to MEET the CONSTANT value.
The model with lesser x would need to have a value added to it and the model with more x would have a value deducted from it. We add the added value and the deducted value from both models to find out the difference between the number of x in each model.
(so model-1 has 2x and model-2 has 3x. we add up the added value from model-1 and deducted value from model-2 we will find out the difference between 2x and 3x, which is the value of 1x)
Concept in this question is the constant value and variable value.
This method can be used in our daily life, such as comparing prices of 2 different stores.
An example would be:
Store A sells Book of XYZ for $20 before a discount of 5% and Store B sells the same book at $30 before a discount of 20%.
The method would thus allow us to see which store sells the book at a cheaper price.