Teacher Xie bought curtains for the school computer room. I bought 12 meters for the first time, and bought 8 meters of the same cloth for the second time. The second time cost 13.6 yuan less than the first time. How much is it per meter cloth?
谢老师为学校机房买窗帘．第一次买了12米，第二次买了同样的布8米，第二次比第一次少用了13.6元．每米布多少元？
<gadget id="calculator">12 - 8</gadget>
<output>4</output>

<gadget id="calculator">13.6 / 4</gadget>
<output>3.4</output>

<result>3.4</result>