Question 549027
We know that the Probability of a pizza and salad is 65%.  
We also know the probability of a pizza is 95%.  

This means that 95%-65%=30% of the customers order just a pizza.   
This 30% is 30% of the total people.  

Let's look at a quick example.  Say we have 100 people.  
This means that 95 people have a pizza (with or without a salad) and 30 people have just a pizza (no salad).  
This means that the probability of just pizza looking at the total of people who ordered pizza is {{{30/95=31.6%}}}


Without an example we could have done 
{{{0.3/0.95=31.6%}}}




Hopefully this helps ((this is just a conditional probability, if you want the more general form, search CONDITIONAL PROBABILITY))

:)