Janet is three times older than her sister julie. janet's brother is eight years younger than their sister julie. the sum of all ther age is 55 years

Let x= the age of julie
3x= the age of janet
x-8= the age of Janet's brother

x+3x+(x-8)=55
5x-8=55
+8 +8
5x=63
- -
5 5
x=12.6

:. 3x
3(12.6)
37.8

:. x-8
12.6-8
4.6

CHECK
12.6+37.8+4.6

:. Julie is 12.6 years old, Janet is 37.8 years old, and their brother is 4.6 years old.