Answer:
0.3
Explanation:
the total of all probabilities is 1.00, or 100%.
In the Venn diagram, we have the probabilities 0.2, 0.4 and 0.1; these sum to
0.2+0.4+0.1 = 0.6+0.1 = 0.7.
This leaves us 1.00-0.7 = 0.3 for the remaining probability of no toppings.