Derive the equation of the parabola with a focus at (2,4) and a directrix of y=8

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

You give a $4 tip for a meal that cost $22. approximately what percent of the bill was your tip?

What is the value of x when x + 7 = 21?