A snail and an earthworm start from point A on the circle at the same time, and go around the circle opposite to each other. It takes 6 minutes for the snail to climb the first circle, and the time required for each subsequent circle is 1 minute longer than the previous circle. It takes 5 minutes for the earthworm to crawl the first lap, and the time required for each subsequent lap is 4 minutes longer than the previous lap. How many minutes after they set off, they meet again at point A.
一只蜗牛和一只蚯蚓从圆上一点A同时出发，绕圆周相背而行，蜗牛爬第一圈需要6分钟，以后每爬一圈所需要的时间都比前一圈多1分钟．蚯蚓爬第一圈需要5分钟，以后每爬一圈所需要的时间都比前一圈多4分钟．在它们出发以后多少分钟，它们又在A点相遇．
<result>90</result>