Asked by Frank Minimi

n a Star Trek episode, a population of tribbles (average weight of 56 grams) invade a Klingon starship. The Klingons enjoy eating the tribbles they can find. A Romulan spy smuggles the remaining tribbles (average weight of 21 grams) to Romulus prime. The offspring of the smuggled tribbles have an average weight of 23 grams.
What is the selection differential (S) for this event?