Final answer:
To find the total fraction of the lawn mowed by Melvin before his first break, one would add the additional 3/10 to the already mowed fraction represented by the shaded model.
Step-by-step explanation:
The student's question is about calculating the fraction of the lawn that will be mowed by Melvin before he takes his first break. Initially, the question does not specify what fraction of the lawn is already mowed, but indicates that Melvin will mow an additional 3/10 of the lawn. Assuming that the shaded model represents the fraction already mowed (let's say x), the total fraction mowed before Melvin's first break would be x + 3/10. Without the specific value of the initially mowed fraction, we cannot provide the exact answer; however, generally, the operation would involve adding the given fraction to Melvin's progress before he mows the additional 3/10.