Answer:
The answer is: David should make pizza and John should make pasta.
Step-by-step explanation:
John is more efficient at producing both pizza and pasta, but considering he can only make one at a time we calculate David´s productivity compared to John´s.
David is 80% as productive as John in making pizza, and only 75% as productive in making pasta.
David should be in charge of making pizza because his productivity is closest to John´s.