There would be a 65% chance of picking a customer who orders one or the other.
Step-by-step explanation:
In order to find this, we first must find the percentage that orders only pizza. We can do this by subtracting the overlap from the total number.
75% - 15% = 60%
We need to do the same thing for salad.
20% - 15% = 5%
Now that we have the percentages who ordered just one or the other, we can add them together to get the total percentage who got either one or the other.