Problema Solution

A girl is one-third as old as her brother and 8 years younger than her sister. The sum of their ages is 38 years. How old is the girl?

Answer provided by our tutors

let


g = the age of the girl

b = the age of her brother

s = the age of her sister


a girl is one-third as old as her brother and 8 years younger than her sister


g = (1/3)b


g = s - 8


the sum of their ages is 38 years


g + b + s = 38


by solving the system of equations


g = (1/3)b

g = s - 8

g + b + s = 38


we find


g = 6 years


b = 18 years


s = 14 years


the girl is 6 years old.