I do believe that the answer is 9/10
Rotation and translation are rigid transformations, they don't change figure sizes. Dilation change figure sizes increasing or decreasing them by scale factor.
First, find AB and A'B' by the formula:

As you can see AB=2A'B'. This means that the segment AB was decreased twice to form segment A'B'. Then the scale factor is 1/2.
Hello.
To find the percentage of how many students went on the field trip, we simply divide 18 by 25.
18/25 = 0.72
Convert decimal into fraction.
0.72 = 72%
Thus, 18 out of 25 students = 72% of students who are going on the field trip.
You're welcome.