at 1000am a car leaves a house at a rate of 60mih at the sam

at 10:00am a car leaves a house at a rate of 60mi/h. at the same time, another car leaves the same house at a rate of 50mi/h in the opposite direction. at what time will the cars be 330 miles apart?

Solution

First the easy way. You can do it in your head. They are separating at the rate of 60+50 or 110 mi/h. So at that rate it would take them 3 hours to be separated by 330 miles. That would be at 1PM. But your teacher doesn\'t want you to do it this easy way. So here is the way your teacher wants you to do it: Let t = the number of hours after 10 AM when they will be 330 miles apart Make this DRT-chart: Distance Rate Time 1st car 2nd car They both travel the same length of time. So fill in t for both times. Distance Rate Time 1st car t 2nd car t Their rates are 60 and 50, so fill those in for the rates. Distance Rate Time 1st car 60 t 2nd car 50 t Now use D=RT to fill in the distances: Distance Rate Time 1st car 60t 60 t 2nd car 50t 50 t Now the sum of the two distances must equal 330 miles. So we have the equation: 60t + 50t = 330 110t = 330 t = 3 So it will take 3 hours after 10AM, or 1PM.