A car and a truck leave opposite directions from towns A and B at the same time. They meet for the first time at a distance of 15km from the midpoint. Return immediately after arriving at town B, catch up with the truck 30km away from town A, find the distance between A and B.
一辆轿车和一辆卡车同时从甲乙两镇相向开出，第一次相遇在距中点15km处，相遇后，卡车速度不变，小轿车提速(1/5)，继续行驶，小轿车走到乙镇后立即返回，在距甲镇30km追上卡车，求甲乙两地距离．
<result>70</result>