Given,
Speed of the car = 60km/hr
Time taken by the car = 12 hours
Distance to be travelled = (60 x 12) km = 720km
Therefore, the speed to be increased in 10 hours = \(frac{720}{10}\) km/hr = 72 km/hr
So, the difference in the speed = (72 – 60) km/hr = 12km/hr