A family in Singapore part 24 (Math Question)

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The blog postings are about the Singapore Math. The readers can learn from the postings on Solving Singapore Primary School Mathematics that teaches in Singapore Primary Schools. You or your kids can learn the skills of dealing with Math Modeling, Math Problem Solving, 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 Fraction, Ratio, and Problem Sum.

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

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

Should read also the posting on Sarin learns the concept of Fraction (mathematics concept) to understand the concept of Fraction.

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

Upper primary school mathematics question UPQ288

Sarin and Hairu received some money from their father. At first, Sarin had $200 less than Hairu. Then Hairu gave Sarin 1/4 of his money. In return, Sarin gave Hairu 1/5 of his money. Later, Hairu gave 1/2 of his money to Sarin.  In the end, Sarin had $700 more than Hairu. How much did each of them have at first?

 Solution:

Using Math Model,

            Start with Sarin had $200 less than Hairu

 

 

            Sarin received ¼ of the fraction of Hairu’s money

 

 

            Sarin given 1/5 of the fraction of his money to Hairu

 

 

            Sarin received ½ of the fraction of Hairu’s money and Sarin had $700 more than Hairu finally

 

 

                        Per the final model

                        4 units + 40 + 80 = 80 + 700

                        4 units = 660

                        1 unit = 165

                        The amount of money Sarin had at first = 4 × 165 = $660

                        The amount f money Hairu had at first = 4 × 165 + 200 = $860

Alternative Solution:

Use ratio,

                        Set the amount of money that Sarin had at first as 1U

                        Initially, Sarin had $200 less than Hairu

                        In ratio, Sarin : Hairu = 1U : (1U + 200)

                        ¼ of the fraction of Hairu’s money gave to Sarin,

                        Sarin : Hairu = (1U + ¼ U + 50) : (3/4 U + 150) = (5/4U + 50) : (3/4 U + 150)

                        1/5 of the fraction of Sarin’s money gave to Hairu,

                        Sarin : Hairu = (1U + 40) : (1/4U + 10 + ¾ U + 150) = (1U + 40) : (1U + 160)

                        ½ of the fraction of Hairu’s money gave to Sarin,

                        Sarin : Hairu = (1U + 40 + ½ U + 80) : (1/2 U + 80) = (3/2 U + 40) : (1/2 U + 80)

                        Finally, Sarin had $700 more than Hairu,

                        3/2 U + 40 – ½ U – 80 = 700

                        1U = 660

                        The amount of money Sarin had initially = $660

                        The amount of money Hairu had at initially = 660 + 200 = $860

 

 More Questions on Fraction & Ratio. Click here….

 More Questions on Problem Sum. Click here…

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2 responses »

    • Thanks for sharing your experience on Singapore Math. We start our kids on simple blocks and drawing so that they can visual the math question easy and quickily. They need not require to know equations but simple concept that help solve a complex question.

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