# Sarin and his coin bank part 22 (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 aquire the skills of dealing with Math Model, Problem Sum start from Lower Primary School to Upper Primary School level after read the postings. This posting is an Upper primary school math question on Fraction, Ratio and Problem sum.

You can read posting Sarin and his coin bank on the story of coin bank.

You should read the posting on Sarin learns concept of ratio in school to understand mathematics concept of Ratio and read the posting on Sarin learns the concept of Fraction (mathematics concept) to understand Fraction and Portion.

Let try to solve the Question before you look out for the solution‼!

Upper primary school mathematics question UPQ247

Sarin and Hairu each have some savings in their coin banks. If Sarin saves another \$88, the ratio of Sarin’s savings to Hairu’s savings will become 3 : 4. If Hairu saves another \$88, the ratio will become 8 : 13. How much have the two of them save altogether?

Solution:

Draw the model based on both additional saving cases

From the above model,

(8U + 88)/3 = (13U – 88)/4

32U + 352 = 39U – 264

7U = 616

1U = 88

The amount of money two of them saved = 21 × 88 – 88 = \$1760

Alternative solution:

In both cases, both of the additional saving is \$88 each.

The total saving with the additional saving both bothcase are the same.

The problem can be deal with by equal total approach.

Ratio of saving,

Sarin save \$88 more, Ratio of Sarin : Hairu : all = 3 : 4 : 7 = 9 : 12 : 21

Hairu save \$88 more, Ratio of Sarin : Hairu : all = 8 : 13 : 21

The different in saving for Sarin in both case is 1 unit = \$88

The amount of saving for both of them = 21 × 88 – 88 = \$1760