Question posted by Jil from Singapore:

Andrew had $268 and Brett had $172 at first.

Each bought a pair of skates at the same price.

After their purchase, Andrew had five times as much money as Brett.

How much did each pair of skates cost?

Answer:

Step 1: We will start by drawing the "After" model, i.e., the model to represent what happens after the purchase of the skates. Draw 5 boxes and 1 box to represent how much money Andrew and Brett had left respectively after buying the skates.

Step 2: Draw 2 equal boxes to represent the money spent on skates by both of them. This is the "Before" model.

Step 3: Label the model to show the amount of money each of them had before buying the skates, namely $268 and $172.

Step 4: From the model, we can see that the difference between $268 and $172 is represented by 4 boxes or 4 units. We label the 4 units with a "?".

Therefore,

4 units ----------> $268 - $172 = $96

1 unit -----------> $96 / 4 = $24

From Brett's portion of the model, we can see that,

Cost of a pair of skate = $172 - $24 = $148