I have gotten some basics from this question, but cannot think of the formula to match it. Too much information and I am lost.. PLEASE HELP!!!!

At the time she was hired as a server at the Grumney Family restaurant, Beth Brigden was told, “You can average more than $20 a day in tips.” Over the first 35 days she was employed at the restaurant, the mean daily amount of her tips was $24,85, with a standard deviation of $3.24. Can Ms. Brigden be 99% confident that she is earning an average of more than $20 per day in tips?

Mean: $24.85

Standard Deviation: $3.24