Xiao Ming and Xiao Hua go swimming in the swimming pool together. Xiao Ming goes first, walking 36 meters per minute. After 2.5 minutes, Xiao Hua sets off and walks 45 meters per minute. After how many minutes can Xiao Hua catch up with Xiao Ming?
小明和小华一起去游泳馆游泳，小明先走，每分钟走36米，2.5分钟后，小华出发，每分钟走45米，多少分钟以后小华可以追上小明？
<gadget id="calculator">36 * 2.5</gadget>
<output>90</output>

<gadget id="calculator">45 - 36</gadget>
<output>9</output>

<gadget id="calculator">90 / 9</gadget>
<output>10</output>

<result>10</result>