Convert 0..489 to scientific notation

Do some research and find a city that has experienced population growth. determine its population on january 1st of a certain year. write an exponential function to represent the city’s population, y, based on the number of years that pass, x after a period of exponential growth. describe the variables and numbers that you used in your equation.

You are at a restaurant and owe $38 for your meal. you want to leave a 20% tip. how much will your tip be?

Anyone? 15m is what percent of 60m; 3m; 30m; 1.5 km?