A car left town a for town b. another car left town b for town a at the same time. the ratio of the speeds of the two cars was 6:5 initially. after the two cars passed each other, car a's speed was reduced by 1/6 and car b's speed was reduced by 25%. when car a arrived at town b, car b was still 54 km away from town a. find the distance between town a and town b. please i need the answer quickly :]