A family in Singapore part 61 (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, 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 Fraction and  Problem solving.

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

Read 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 UPQ568

Sarin and Hairu shared a sum of $200. Sarin gave 3/5 of what he has to Hairu. Hairu later gave 1/5 of what he has back to Sarin. They ended up with equal amount of money. How much did Sarin have at first?

 Solution:

The total amount did not change in this case.

Sarin and Hairu at the end have equal amount of money.

At the end, each of them has $100.

Hairu given 1/5  of his money to Sarin at the final stage,

So the amount $100 he had finally was 4/5  of the his amount before that

4 units = $100

1 unit = $25

Hence,

Hairu have before = 100 + 25 = $125

Sarin have before = 100 – 25 = $75

It was Sarin that giving Hairu 3/5  of his money first,

The amount of $75 was 2/5 of what he has at first,

2 units = 75

1 units = $37.5

The amount Sarin has at first = 5 × 37.5 = $187.50

Alternative solution:

Using of model,

Start with final model and reverse the process

Hairu gets back 1/5  of his money from Sarin

upq568-1

Sarin then gets back 3/5 of his money from Hairu and the model shown the ‘at first’ scenarios.

upq568-2

From the model (at first),

16 units = 200

1 unit = $12.5

The amount Sarin had at first = 15 × 12.5 = $187.5

More Questions on Problem solving. Click here….

More Questions on Ratio and Fraction. Click here…..

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