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

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

Read also the posting on** ****Sarin learns Symbol, Algebra and Equation in school (Math Concept)**** **to understand the concept of Algebra.

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

**Upper primary school mathematics question UPQ409**

Fatimah’s father is 48 years old and Fatimah is 6 years old. In how many years’ time will Fatimah’s father be four times as old as Fatimah?

Solution:

Using Algebra Expression

Whenever a year pass, both Fatimah and her father will be additional 1 year older

After Some years (x),

Fatimah will be (6 + x) years old

Fatimah’s father will be (48 + x) years old

Fatimah’s father is 4 times as old as Fatimah

Fatimah’s age after x years will be = 4 (6 + x) = (24 + 4x)

The model

From the model

3 units = 48 – 24 = 24

1 unit = x = 8 years

In 8 years times, Fatimah’s father will be 4 times as old as Fatimah

Alternative Solution(1):

After some years

Father’s age is 4 times of Fatimah’s age

Rearrange the model with the above information

From the above model

3 units = 48 – 6 = 42

1 unit = 14 years

The some years = 14 – 6 = 8 years

In 8 years times, Fatimah’s father will be 4 times as old as Fatimah

Alternative Solution(2):

Sub-divide the some years more to 4 parts and redraw the model

From the model

3 units = 12 – 6 = 6 years

1 unit = 2 years

The number of years = 2 × 4 = 8 years

In 8 years times, Fatimah’s father will be 4 times as old as Fatimah

Alternative Solution(3):

Express using ratio

Present age ratio

The ratio of Father’s age to Fatimah’s age = 48 : 6

Age ratio after some years (x)

The ratio of Father’s age to Fatimah’s age = 4 : 1 = (48 + x) : (6 + x)

48 + x = 4 × (6 + x)

48 + x = 24 + 4x

3x = 48 – 24 = 24

x = 8 years

In 8 years times, Fatimah’s father will be 4 times as old as Fatimah