Explanation:
In my picture I made 6 slices, with one slice twice as large as the others.
Pretend that we cut the sausage slice in half. Then there would be 7 slices total.
We want to find P(Not Sausage).
Well since we sliced the big slice in two, we have 7 slices total. There are 5 slices without sausage.
The probability of getting a slice without sausage would then be 5/7.