Question

How can I explain this process in response to the question: How many boats can have registration numbers starting with 6?

Answer 1

c=n!/(n-r)!
c=7!/(7-7)!
c=5040

Answer 2

here is the explaination i have:

Answer 3

The combinations method was also used to calculate the number of boats that can have registration numbers staring with six.

Answer 4

question is not clear