Question about probability/proportion/sample

[ThomasPaine1]

We notice that 7% of clients don't arrive on time. Within a sample of 100 clients, what would be the probability that the proportion of people that don't arrive on time is greater than 9%?

I think the answer has to do with this equation, but this equation provides an interval rather than a probability so I'm not sure.

 

[blamocur]

I cannot comment on the equation since I don't understand what it means and how it can be applicable to you problem.
My preference would be to try the Central Limit Theorem since 100 is a pretty large number (https://en.wikipedia.org/wiki/Central_limit_theorem).