SOLUTION: increasing the average speed of a car by 12 mph results in a 189 mile trip taking an hour less than before. What was the orginal average speed of the car?
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Question 452586: increasing the average speed of a car by 12 mph results in a 189 mile trip taking an hour less than before. What was the orginal average speed of the car? Answer by jorel1380(3719) (Show Source):
You can put this solution on YOUR website! 189/x=189/(x+12)+1
189(x+12)=189(x)+x2+12x
189x+2268=189x+x2+12x
x2+12x-2268=0
(x+58)(x-46)=0
x=46 or -58
Throwing out the negative answer, we get the original speed of the car to be 46 mph..
