I need help finding the are and perimeter but I have to explain too please help.

About 400,000 people visited an art museum in december. what could be the exact number of people who visited the art museum?

Last year, a state university received 3,560 applications from boys. of those applications, 35 percent were from boys who lived in other states. part a)how many applications did the university receive from boys who lived in other states? part b)applications to the university from boys represented 40percent of all applications. how many applications did the university receive in all? i don't how to do part b so me and plz tell how you got your answer

In a class, there are 12 girls. if the ratio of boys to girls is 5: 4 how many boys are there in the class