While travelling towards goa from Mumbai, Ganesh saw milestone with two digits indicating the distance of that point from Mumbai. After travelling some distance, he saw another milestone with the same digits but in reverse order. Further travelling the same distance that he had travelled from the 1st milestone to the 2nd milestone, he saw another milestone with a 3-digit number that had the same digits but also had a zero in it. But the order of the digits was different. His speed was uniform through out the journey. The distance between the 3rd and 1st milestone is :