Answer:
The probability of a big storm is 40%.
Now, you can find a D10 (a die with 10 faces)
You can assign 4 numbers (0, 1, 2, 3) to the event "there is a major storm"
in this way, you have 40% of having a storm.
and the other 6 numbers (4, 5, 6, 7, 8, 9) to the event "there is not a major storm". This means that we have 60% of not having a storm.
now, when you roll the dice you can see if a year there will be a storm or not.
Now, you roll the dice 5 times (for the 5 years) and take note of the results and the number of storms in those 5 rolls.
Now do the same thing a bunch of times, at least 25 times.
Now, you recorded the results in each set of rolls, now see the number of sets that have at least years with storms.
Take that number and divide it by the total number of sets of data (in this case 25, for example)
The result is the probability that we are looking for.