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, the Math Questions with solutions that teaches in Singapore Primary Schools. You or the kids will able to acquire knowledge of dealing with the Math Modeling, the Math Problem Solving and the 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, and Average Number.

You can click here and read the posting **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.

You should read the posting on **Sarin learns Average Number, Percentage and Charting in school (Math Concept)**** **to understand the concept of Average Number.

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

**Upper primary school mathematics question UPQ423**

The mass of Fatimah, Sarin and Hairu is in the ratio of 3 : 5 : 2. If Hairu’s mass is 24 kg, what is the average mass of three of them?

Solution:

The mass ratio of three of them

Fatimah : Sarin : Hairu = 3 : 5 : 2

Hairu is 24 kg

2 units = 24 kg

1 unit = 12kg

The mass of Fatimah = 3 × 12 = 36kg

The mass of Sarin = 5 × 12 = 60kg

The total mass of three of them = 24 + 36 + 60 = 120kg

The average mass of three of them = 120 ÷ 3 = 40kg

Altrernative solution:

The mass ratio model of three of them

Subdivide the each identical model block to 3

The new mass ratio model for three of them

To find average mass, redistribute the blocks equally to all three.

From the model

6 units = 24kg

1 unit = 4kg

The average mass = 10 × 4 = 40kg

To note: we subdivide each block by 3, as there are 3 people’s mass. This is to make it able to redistribute the subblocks.

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