Ajay goes to his office from his house at a speed of 18 km/hr and returns to his home from his office at a speed of 36 km/hr and he takes 8 hours in all. If the distance of his friend's house from his office is 15% more than the distance of his house from his office, find the distance of his house to his friend's house. (Assuming the office lies between Ajay's house and his friend's house)