SOLUTION: A car travels a distance of900 km with a certain average speed. After travelling half the distance, if the average speed of the car is increased by 15 km/hr,the time required to tr
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Question 1013233: A car travels a distance of900 km with a certain average speed. After travelling half the distance, if the average speed of the car is increased by 15 km/hr,the time required to travel the remaining distance is reduced by 3/2 hours.find the original average speed or the car. Answer by Alan3354(69443) (Show Source):
You can put this solution on YOUR website! A car travels a distance of900 km with a certain average speed. After travelling half the distance, if the average speed of the car is increased by 15 km/hr,the time required to travel the remaining distance is reduced by 3/2 hours.find the original average speed or the car.
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r = lower speed in km/hr
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450/r = 450/(r+15) + 3/2
300/r = 300/(r+15) + 1 = (315+r)/(r+15)
r*(315+r) = 300*(r+15)
r^2 + 315r = 300r + 4500
r^2 + 15r - 4500 = 0
r = 60 km/hr
