Two missiles are initially 5000 miles apart. They travel along a straight line directly towards one another, one traveling at 2000 miles per hour and the other at 1000 miles per hour. How many miles apart are they 1 minute before impact?

First, you must add the two rates together, since the object are heading together:                                                                                                                                                                            2000 + 1000 = 3000                                                                                                                                                                                    Next, you simply divide that by 60 to find the rate of miles per minute:                                                    
                         3000 / 60 = 50                                                                                                                                                                                                                                  50 miles is going to be your answer since this is the last minute before impact. This means that in another minute, they will travel 50 more miles and collide