Answer: Michelle visited 24 more lighthouses in Maryland than in Virginia.
Explanation:
Based on the information given in the exercise, you know that Michelle visited a total of 30 lighthhouses.
You can express the percent in decimal form by dividing it by 100. Then:

Let be "V" the number of lighthouses Michelle visited in Virginia. Since it is the 20% of the 30 lighthouses, this is:

Let be "M" the number of lighthouses Michelle visited in Maryland (
). This is:

Therefore, you can determine that Michelle visited 24 more lighthouses in Maryland than in Virginia.