Question

the difference in age between a girl and her youger sister is 4 years.theyounger sister in turn is 4 years older than her brother.the sum of their ages of the younger sister and her brother is 16.how old are the three children

Answer 1

let the girls age be x ,the sister be y,and the brother be x years old
according to the given conditions,

x-y=4 eq 1

y=4+xz

ie y-z=4 eq 2

y+z=16 eq 3

add eq 2 and eq 3
we get

2y=20
y=10

using y =10 in eq 1 and eq 2
we get

x=14 and
z=6
therefore,the elder girl is 14.sister is 10 and the brother is 6 years old.