Final answer:
The cost of tuition when a student registers for 15 credits is approximately $528 (in hundreds of dollars).
Step-by-step explanation:
To estimate the cost of tuition, T, when a student registers for 15 credits, we can use the given equation: T = 3 + 35c. Here, c represents the number of credits.
Substituting the value of 15 for c, we get: T = 3 + 35(15).
Simplifying, we find that T = 3 + 525 = 528. Therefore, the estimated cost of tuition when a student registers for 15 credits is $528 (in hundreds of dollars).