Grade 5 - Posted on Wednesday

Zach, the question of Evan has #2.55 more than Richard. Jonas has four times as much money as Even. The 3 boys have $24.15 altogether. How much money does Jonas have?

Your Answer: You have added $2.55 to $24.15 i.e. $26.70 and then divided by 6 units. Zach, the question has mentioned that altogether 3 boys have $24.15. Please clarify. Thanks.

Here's My Answer
by Zach
(Singapore)

Hi Kplybon,

Yes, the actual amount that the 3 boys had was $24.15. However, $24.15 is made up of 5 equal units and 1 smaller unit. In order to solve the question, we need to make all the unknown units equal so that we can divide all 6 unknown units by 6 to get the value of 1 unit.

The value of $26.70 is an artificial one. It does not exist. It is merely created to facilitate our calculation. That's why when we add $2.55 to the model, we also add $2.55 to the total value making it $26.70.

We are more interested in getting the value of 1 unknown unit which will, in turn, help us to calculate the value of 4 units (J's share).

Hope that helps. Feel free to ask again if I am still unclear in my explanation.