To comprehend let’s assume:
100 relatives as 100 tiles
Now, 90 Dutch people fills 90 tiles.
Since we require minimum common people as the question
suggests we need to make common tiles less in Number.
80 German people fills 10 empty tiles and 70 Dutch people tile.
Now 10 German tiles, 20 Dutch tiles and 70 common tiles.
Again do the same, fill non common tiles first with English. i.e.
10 German + English, 20 Dutch + English.
So only 45 Dutch + German + English.
Hence 45 is the answer.
