Zhang Ling's home is 630 meters away from the Children's Palace. How long does it take for her to go back and forth at a speed of 90 meters per minute?
张玲家离少年宫630米，她以每分钟90米的速度往返一次，共需要多少时间？
<gadget id="calculator">2 / 90</gadget>
<output>1/45 = around 0.022222</output>

<gadget id="calculator">630 * (1/45)</gadget>
<output>14</output>

<result>14</result>