Question

The ratio of the number of Julia's sports cards to the number of Alexis sports cards is 1:3. Together, they have 28 sports cards. How many sports cards does Julia have?

Answer 1

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

Answer 2

Julia has 7 sports cards.