Answer :
Assume Julie is x years old
(x+3)+x+(x-8)=55 Julie is 20 years old
3x-5=55 Janet is 23 years old
3x=60 brother is 12 years old
x=20
(x+3)+x+(x-8)=55 Julie is 20 years old
3x-5=55 Janet is 23 years old
3x=60 brother is 12 years old
x=20
Let us assume age of Julie to be x years this implies age of janet is (x + 3) years and age of Janet's brother is (x - 8) in this way we will solve for x and find out everyone's age.
How we are assuming and constructing ages from the given question and forming them into mathematical expressions ?
here we have taken x years for the person having least age for our convenience.Her sister is 3 years older than her so her age addition to 3 years.Her elder brother is 8 years younger than her sister so her sister's age less to 8 years.
in the given question sum of their ages is 55
So,
[ x + (x + 3) + (x - 8) ] = 55
3x - 5 = 55
3x = 60
x = 20
So, Julie's age is 20 years
Janet's age is 20 +3 = 23 years
Janet's brother's age is = 20 - 8 = 12 years.
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