There are 2 colored ribbons, the red colored ribbon is 45 cm long and the yellow colored ribbon is 30 cm long. Cut the two colored ribbons into short colored ribbons of the same length and there is no surplus. What is the longest length of each short colored ribbon?
有2根彩带，红彩带45厘米，黄彩带30厘米，把两根彩带剪成长度一样的短彩带且没有剩余，每根短彩带最长多少厘米？
<gadget id="calculator">3 * 5</gadget>
<output>15</output>

<result>15</result>