John and alan have a collection of x baseball cards. john has x4 cards. what fraction of the cards does alan have?

Number of cards of John: J
Number of cards of Alan: A

John and Alan have a collection of x baseball cards:
J+A=x    (1)

John has x/4 cards:
J=x/4

What fraction of the cards does Alan have?

Replacing J by x/4 in the equation (1)
(1) J+A=x
x/4+A=x

Solving for A:
x/4+A-x/4=x-x/4
A=4x/4-x/4
A=(4x-x)/4
A=3x/4

Alan has 3/4 of the cards 

Sorry i meant b in the other question