Answer:
of the burgers were well done
Explanation:
Firstly, we are told that a total of 50 burgers were served at Kayla's Burgers, this represents the
.
In additon, we are told 15 of that burgers were cooked well done and we need to know which percentage they represent. This can be calculated by the Rule of Three as follows:
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Then:

This means that
of the burgers were well done