Sarin and his mother Part 1 (Math Question)

Standard

Upper primary school mathematics question UPQ2

Sarin and his mother have a total age of 100. 8 years ago, his mother’s age was 3 times that of Sarin’s age. How many years later will Sarin’s age be half that of his mother?

Solution:

 

100 – 8*2 = 84

8 years ago, Sarin’s mother is 3 time his age. So

Sarin age is 84/4 + 8= 29 years old

And his mother is 21*3 + 8 = 71 years old

 

Note: When Sarin older by one year, his mother also older by one year.

Ratio of age of Sarin and his mother is 1:2 after X years

ANS: After 13 years, age of Sarin’s mother is two time of Sarin’s age.

Alternative Solution:

            There are 100years old in total this year

            Mother = 71 years old

            Sarin = 29 years old

            After some years mother will be twice the age of Sarin

            Draw the math model

UPQ2-4

 

 

            From the model

            1 unit = 71 – 29 = 42years

            The number of years that mother’s age will be twice Sarin’s age = 42 – 29 = 13 years

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