Q: A combination lock uses the numbers from 0 to 59.

Question

1.A combination lock uses the numbers from

0 to 59. Three numbers are dialled in the

correct sequence. How many unique lock

combinations are possible

a) if repetition is permitted? <- why isn't it 59x59x59? It doesn't make sense to me. (0-59)

b) if repetition is not permitted?

Answer 1

There are 60 integers between 0 and 59 inclusive, but your logic is correct.

If repetition is not permitted, it goes down to 60·59·58.