Let A = amount of Alan's money (shares ?)
B = amount of Bob's money.
The condition says that = 2. (1)
Simplify the ratio in the left side, step by step. You will have
= = + = + = + = + .
So we can write (1) in an equivalent form
+ = 2,
which implies
= - , ====> = ====> = = .
Answer. The ratio of Alan' share to Bob' share at first was = .