by Christina Yuen

(Singapore)

Hi Zach,

Could you advise how to solve this question? Kindly guide on the model drawing too.

Thanks!

The question is:

A watch costs $25 more than a calculator. 3 such watches cost as much as 8 such calculators. What is the cost of each calculator?

Step 1: This question involves the Comparison Concept and the Repeated Variable Concept. Since A watch costs $25 more than a calculator, we draw 1 box to represent the amount of money a calculator cost and draw an identical box plus another box marked with "$25" to show that the watch cost $25 more than a calculator.

To see the rest of the answer, click here