There is a document of 5,700 characters. Two typists, A and B, print it at the same time. A types 100 characters per minute, and B types 90 characters per minute. How long does it take to finish typing this document?
有一份5700字的文件，甲乙两个打字员同时打印，甲每分打100个字，乙每分打90个字，打完这份文件需要多少时间？
<gadget id="calculator">100 + 90</gadget>
<output>190</output>

<gadget id="calculator">5_700 / 190</gadget>
<output>30</output>

<result>30</result>