What is 645 rounded to the nearest ten

Two cars which are 40 miles apart start moving simultaneously in the same direction with constant speeds. if the speed of the car which is behind is 56 mph and the speed of the other car is 48 mph, how many hours will it take for the car which is behind to catch up the car ahead of it?

Find the maximum value of p= 4x + 5y subject to the following constraints :

Question 4 of 10 2 points what is the second part of the process of investigating a question using data? a. rephrasing the question o b. describing the data c. collecting the data o d. making an inference submit