The difference in age between a girl an her younger sister is 4years. ...
Given information:
- The age difference between a girl and her younger sister is 4 years.
- The younger sister is 4 years older than her brother.
- The sum of the ages of the younger sister and her brother is 16.
To find: How old are the three children?
Solution:
Let's assume the age of the younger sister as Y years, the age of the girl as G years, and the age of the brother as B years.
Establishing the first equation:
The age difference between the girl and her younger sister is 4 years.
So, we can write the equation:
G = Y + 4 ---(1)
Establishing the second equation:
The younger sister is 4 years older than her brother.
So, we can write the equation:
Y = B + 4 ---(2)
Establishing the third equation:
The sum of the ages of the younger sister and her brother is 16.
So, we can write the equation:
Y + B = 16 ---(3)
Substituting equations (1) and (2) into equation (3):
Substituting the values of G and Y from equations (1) and (2) into equation (3), we get:
(B + 4) + B = 16
Simplifying the equation:
2B + 4 = 16
2B = 16 - 4
2B = 12
B = 12/2
B = 6
Substituting the value of B into equation (2):
Y = B + 4
Y = 6 + 4
Y = 10
Substituting the value of B into equation (1):
G = Y + 4
G = 10 + 4
G = 14
Conclusion:
So, the age of the younger sister is 10 years, the age of the girl is 14 years, and the age of the brother is 6 years.
The difference in age between a girl an her younger sister is 4years. ...
Let the age of bigger girl xthe age of younger girl x-4the age of younger boy x-8x-4+x-8=162x-12=162x=16+122x=28x=28÷2x=14x-4=10x-8=6
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