Respuesta :
let james be x years old
joe = 10+x
after 8 years
18+x =3(x)
18+x=3x
18=2x
x=9
joe is 19
james is 9
joe = 10+x
after 8 years
18+x =3(x)
18+x=3x
18=2x
x=9
joe is 19
james is 9