Sarin’s family and The Great Singapore Sale Part 10 (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 presents the Math Concept, the Math Questions with solutions that teaches in Singapore Primary Schools. You or the kids can acquire the skills to deal 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 Problem Solving.

Read the posting on Sarin’s family and The Great Singapore Sale in the Welcome category for the story.

You can read the posting onSarin learns concept of ratio in school to understand the concept of Ratio.

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

Upper primary school mathematics question UPQ459

It was The Great Singapore Sale. When Fatimah and her mother went to a sale at Metro Department Store, her mother had 3 times as much money as Fatimah. After Fatimah spent $9 and her mother spent $55, Fatimah had 5 times as much money as her money. How much money did Fatimah have at first?

Solution:

            Draw the math model

UPQ459-1

            From the model

            3 units = (5U + 9) × 3 = 15U + 27

            14U = 55 – 27 = 28

            1U = 2

            The amount of money Fatimah has at first = 2 × 5 + 9 = $19

Alternative solution:

            In ratio

            Fatimah : Mother = 1 : 3

            After Fatimah spent $9 and Mother spent $55

            The ratio

            Fatimah : Mother = (1U – 9) : (3U – 55) = 5 : 1

            Therefore,

            1U – 9 = 5 × (3U – 55) = 15U – 275

            14U = 266

            1U = $19

            The amount of money Fatimah has at first is $19      

 

More questions on Ratio. Click here…..

More Questions on Problem Sum. Click here…..

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