Let's rank the amount of pizza left from highest to lowest:
5/8 > 1/2 > 1/3 > 1/4
salami > mushroom > broccoli > plain
Then, let's rank the people who ate the least to the most:
Mark > Sophie > John > Tara
The person who ate the most will have the pizza that has the least amount left. This means that Tara ate the plain pizza, then Mark ate the salami pizza. Therefore, we arranged the right trend. Basing on the arrangement, Sophie ate the mushroom pizza.
to find that out, let's divide 8 by (1+9+6) and distribute accordingly.

Answer:
5 ??????????????????????????????????