Answer:
5%
Step-by-step explanation:
Let x represent the percentage of people that have gone to both the park and the beach.
The percentage of people that have gone only to the amusement park = 80% - x% = 80 - x
The percentage of people that have gone only to the beach = 45% - x% = 45 - x
Therefore:
100% = (80 - x) + (45 - x) + (x) + (15)
100 = 80 + 45 + 15 -x - x + x
100 = 140 - x
x = 140 - 100
x = 40%
Therefore 40% of the students have gone to both the park and the beach.
The probability that the student has gone to the beach but not to an amusement park = 45% - 40% = 5%