Purchase of associate

Hi, Sir. Past year Sept 2018 Q4 iii)

Note ii) Daveed purchased a 25% interest in an associate for cash. The associate reported a profit after tax of $16m and paid a dividend of $4m out of these profits in the year end.

Answer: Purchase of associate

Balance (-) profit $16m x 25% (+) dividend received $4m x 25%= $23m -$4m +$1m = $20m ( cost of acquisition)

My question is why the profit has to be minus out and add up the dividend received?