An asteroid is moving directly towards the centre of the earth. When at a distance of 10R (R is the radius of the earth) from the earth's centre, it has a speed of 12 km/s. Neglecting the effect of earth's atmosphere, what will be the speed of the asteroid when it hits the surface of the earth (escape velocity from the earth is 11.2 km/s )? Give your answer to the nearest integer in kilometer/s