The size of the shoe refers to the length of the sole, usually in "yard" or "centimeter", the relationship between them can be expressed by y=2x-10 (y represents the number of yards, x represents the number of centimeters). Xiao Ming bought a new pair of sandals in size 39. How many centimeters is the sole length?
鞋的尺码是指鞋底的长度，通常用"码"或"厘米"作单位，它们之间的关系可以用y=2x-10来表示(y表示码数，x表示厘米数)．小明新买了一双39码的凉鞋，鞋底长多少厘米．
<gadget id="calculator">39 + 10</gadget>
<output>49</output>

<gadget id="calculator">49 / 2</gadget>
<output>49/2 = around 24.5</output>

<result>49/2 = around 24.5</result>