Michelle Theseira's answer to Cherlene wong's Primary 3 Maths Singapore question.

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Michelle Theseira
Michelle Theseira's answer
2 answers (Tutor Details)
Key is to draw the model out and visually understand that Garrett is thrice Sebastian’s age, which works out the ratio of 1:3 within the model.

Although he is three times older, the difference is the same which is 24 years (equivalent to 2 units in the model).

Thus, divide that by two to find out how many years is one unit. Hope this helps!