A family in Singapore part 45 (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 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, Algebra and Problem Sum.

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

You can read the posting Sarin learns Symbol, Algebra and Equation in school (Math Concept) to understand the concept of Algebra.

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 UPQ399

Hairu is 1/5 as old as his father now. In 8 years’ time, he will be 1/3 as old as his father. How old is Hairu now?

 Solution:

            After 8 years, both Hairu and his father will be 8 years older

         Hairu will be 1/3 as old as his father

UPQ399-1

Since Hairu is 1/5 as old as his father now

A yellow block above is Hairu today’s age (Green block) plus 8 years

            UPQ399-2

            From the model

            1 unit = 8 year

            Hairu is 8 years old now

Alternative solution:

            Using algebra and equation

            Set Hairu age now as H

            Father’s age now = 5H          

            Hairu’s age after 8 years = H + 8

            Father’s age after 8 years = 5H + 8

            Hairu is 1/3 as old as father

            Another word, father is 3 times older than Hairu after 8 years

            3 (H + 8) = 5H + 8

            3H + 24 = 5H + 8

            2H = 24 – 8 = 16

            H = 8 years

            Hairu is 8 years old now.

More Questions on Problem Sum. Click here…

More Questions on Fraction. Click here….

More Questions on Algebra and Equation. Click here….

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