In this question, the client will buy one item, which is composed by a boot, a pair of skis and a hat. Since the items are independent, the fundamental counting principle can be used.
Fundamental counting principle:
States that if there are p ways to do a thing, and q ways to do another thing, and these two things are independent, there are p*q ways to do both things.
In this question:
60 boots, 30 pairs of skis, 40 hats. So
60*30*40 = 72,000
The customer can purchase an item in 72,000 ways from the store.
For another example of the fundamental counting principle, you can check https://brainly.com/question/24067651