<em>Missing Information:</em>
<em>It takes Mr. Hamilton 1/15 of an hour to grade one student’s exam and 1/30 of an hour to grade one student’s quiz.</em>
Answer:

Step-by-step explanation:
Given


Required
Determine the time spent on x students
First, we need to determine the total time spent on 1 student


Take LCM



Next is to determine the total time on x students:


A is an equivalent expression
Answer:
P(hit)=0.4
Step-by-step explanation:
In his practice, his probability of getting a hit was 6/15 or 0.4. This counts as an experiment, so the probability of him getting a hit again is the same, 0.4.