Answer:
0.9 is the required probability.
Explanation:
We are given the following in the question:
Percentage of student that have visited the ocean = 70%

Percentage of student that have visited the Mountains = 55%

Percentage of student that have visited the Oceans and Mountains = 35%

We have to find the probability that a randomly selected student has visited the ocean or the mountains.
We have to evaluate:

Putting values, we get,

Thus, 0.9 is the probability that a randomly selected student has visited the ocean or the mountains.