The blog postings are about the Singapore Math. The readers can learn from the postings about Solving Singapore Primary School Mathematics. The blog presenting the Math Concept, Math Questions with solutions that teaches in Singapore Primary Schools. You or the kids will able to acquire knowledge of dealing with Math Modeling, Math Problem Solving and Problem Sum from Lower Primary School to Upper Primary School level after reading the blog postings. This posting is an upper primary school math question on Ratio, Gap Concept and Problem Sum.

You can click here and read the posting on **A family in Singapore** about Sarin’s family.

Read the posting on **Sarin learns concept of ratio in school **to understand the concept of Ratio.

*Challenge yourself with the question before look for the given solution‼!*

**Upper primary school mathematics question UPQ331**

Sarin’s father had given Sarin and Hairu an equal amount of money. Sarin spent $20 each day and Hairu spent $25 each day. When Sarin had $157 left, Hairu had $82 left. How much did Hairu receive from his father?

Solution:

By using gap concept,

Each day, the gap of their spending = 25 – 20 = $5

After certain day, the different of money they left with = 157 – 82 = $75

The number of days they spent the money = 75 ÷ 5 = 15

The amount of money Hairu received from his father = 82 + 25 × 15 = $457

Alternative Solution:

By ratio and math model,

The amount of money Sarin and Hairu spent is fixed each

Ratio of money spent, Sarin : Hairu = 20 : 25 = 4 : 5

Draw the math model

They have equal amount from than add the inform on spending ratio and money left

From the model

1 unit = 157 – 82 = $75

The amount of money Hairu received from his father = 82 + 25 × 15 = $457

**More Questions on Gap Concept. Click here….**

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