If we assume the first ship has a volume ofVL then:

In ship one there will be of coke and so of soda

In ship two there will be of coke and of soda

In ship three there will be of coke and

Add the sum of the coke from the three ships and factor out V.

Add the sum of the soda from the three ships and factor out V

To find the ratio we divide the cola by the soda:

Now we have a ratio of so we multiply by 11 to get an integer ratio of 4:11

(if you're having trouble visualising it try putting V=5)