Question 174532
Since the cars are moving towards each other, you can ADD their speeds together.  The distance between them is closing at a rate of 55 + 70 miles per hour, or a total of 125 mph.  The TIME it takes to close the distance of 20 miles is given by the formula {{{t=d/r}}}, so 
{{{t= 20/125= 0.16}}} hours.



That probably doesn't mean very much to you, so convert this to minutes by multiplying by 60.  That would be 
t= 0.16 hours * 60 = 9.6 minutes.  


Keep that in mind the next time you decide to drink and drive!!!


R^2