The circumference of a circle is 1.26 meters, and two ants start from both ends of the diameter at the same time and crawl towards each other along the circumference. The two ants crawled 5.5 cm and 3.5 cm per second respectively, and they kept turning around during the movement. If the departure is counted as the zeroth U-turn, then the time interval between two adjacent U-turns is 1 second, 3 seconds, 5 seconds, ..., which is a series of consecutive odd numbers. How many seconds have they been crawling when they meet?
一个圆的圆周长为1.26米，两只蚂蚁从一条直径的两端同时出发沿圆周相向爬行．这两只蚂蚁每秒钟分别爬行5.5厘米和3.5厘米，在运动过程中它们不断地调头．如果把出发算作第零次调头，那么相邻两次调头的时间间隔顺次是1秒、3秒、5秒、…，即是一个由连续奇数组成的数列．问它们相遇时，已爬行的时间是多少秒？
<gadget id="calculator">5.5 + 3.5</gadget>
<output>9</output>

<gadget id="calculator">100 / 2 / 9</gadget>
<output>50/9 = around 5.555556</output>

<gadget id="calculator">1.26 * (50/9)</gadget>
<output>7</output>

<gadget id="calculator">1 + 3 + 5 + 7 + 9 + 11 + 13</gadget>
<output>49</output>

<result>49</result>