Sarin’s family celebrating Hari Raya Puasa part 2 (Math Question)

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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 can learn to deal with Math Modeling, Problem Sum from Lower Primary School to Upper Primary School level. This posting is an upper primary school math question on Ratio and Problem Sum.

You can read the postings on Sarin’s family celebrating Hari Raya Puasa and Sarin’s family and Ramadan in Welcome page about story of Sarin’s family during Ramadan and Hari Raya Puasa.

You should read the posting on Sarin learns concept of ratio in school to understand mathematics concept of Ratio.

Challenge yourself with the question before look out for the solution‼

Upper primary school mathematics question UPQ256

Sarin’s family had and open house for friends and relatives on the first day of Hari Raya Puasa. There were 150 friends and relatives visited them before lunch. After lunch, 45 friends and half the relatives had left. The ratio of friends to relatives became 1 : 3. How many friends remained at their house in the afternoon?

Solution:

Draw the model

From the model

7 units = 150 – 45 = 105

1 unit = 15

The number of friends remained in their house = 15

Alternative solution:

Final ratio of friends to relatives = 1 : 3

Half of the relatives left the house in the afternoon

The number of relatives initially in term of units = 3 + 3 = 6 units

45 friends left the house in the afternoon

The number of friends initially = 1 unit + 45

Total number of friends and relatives visited them = 150

6 units + 1 unit + 45 = 150

7 units = 150 – 45 = 105

1 unit = 15

The number of friends remained in their house = 15