Jamal has a drawer containing 6 green socks, 18 purple socks, and 12 orange socks. After
adding more purple socks, Jamal noticed that there is now a 60% chance that a sock randomly
selected from the drawer is purple. How many purple socks did Jamal add?
(A) 6
(B) 9
(C) 12
(D) 18
(E) 24