Respuesta :
1:3 means Alexis have 3 times more sports cards than Julia.
x = Julia
3*x = Alexis
x + 3*x = 28
4*x = 28
x = 7 (Julia)
and 21 for Alexis
x = Julia
3*x = Alexis
x + 3*x = 28
4*x = 28
x = 7 (Julia)
and 21 for Alexis