Item description:

Once the game starts, you (Pauline) will be standing on a boat,
walk towards the front of the boat (go left) and Select X
to interact with the boat's name

Press L2 and select Tablet, then move RS and then press X on screen
["Ship Captain" trophy unlocks]

Once that is done....
Press the "Options" button and select LOAD GAME

Reload the chapter (The very bottom, middle/center one),
talk to Julius or Markus, select "Airplane" then "Money"
and repeat these steps with a different starting price.....

Name one of the amountsand one of the fractions
(I recommend choosing fraction 1/4 every time)
You will then have the option to choose one of three taxes
Choose one, then refuse the price ("Too Much then Stay Firm),
and you will be able to name a different tax

Press the "Options" button and select LOAD GAME and do steps above
until the "Human Calculator" trophy unlocks
(Repeating this will give 3 different prices - IF you do above steps right)

Reidso's Note:
Just mash X to get through text and talk dialogue quicker