Two cars started from the same point, at 5 am, traveling in opposite directions at 40 and 50 mph respectively. At what time will they be 450 miles apart?  Select:  A) 8am  B) 10am  C) 11am  D) 12am  E) 14am
After t hours the distances D1 and D2, in miles per hour, traveled by the two cars are given by   D1 = 40 t and D2 = 50 t   After t hours the distance D separating the two cars is given by   D = D1 + D2 = 40 t + 50 t = 90 t   Distance D will be equal to 450 miles when   D = 90 t = 450 miles   t = 5 hours.   5 am + 5 hours = 10 am   Answer:10am
<result>B</result>
Two cars started from the same point, at 5 am, traveling in opposite directions at 40 and 50 mph respectively. At what time will they be 450 miles apart?