I am unable to solve these two questions can someone help?

A disease has hit a city. The percentage of the population infected t days after the disease arrives is approximated by p(t) = 7te for Osts 45. After how many days is the percentage of infected people a maximum? What is the maximum percent of the population infected? The percentage of infected people reaches a maximum after days. (Simplify your answer.) The maximum percent of the population infected is %. (Round to the nearest hundredth as needed.)