A and B are walking in the same direction. If A asks B to walk 7 meters first, A can catch up with B after 5 seconds; if A asks B to walk first for 2 seconds, A can catch up with B after 7 seconds. How many meters does A walk per second?
甲和乙两人同向而行，如果甲让乙先走7米，5秒钟后甲可以追上乙；如果甲让乙先走2秒钟，则7秒钟后甲可以追上乙．甲每秒钟走多少米．
<gadget id="calculator">7 / 5</gadget>
<output>7/5 = around 1.4</output>

<gadget id="calculator">2 + 7</gadget>
<output>9</output>

<gadget id="calculator">9 - 7</gadget>
<output>2</output>

<gadget id="calculator">7 / 2</gadget>
<output>7/2 = around 3.5</output>

<gadget id="calculator">(7/5) * (7/2)</gadget>
<output>49/10 = around 4.9</output>

<gadget id="calculator">(49/10) + (7/5)</gadget>
<output>63/10 = around 6.3</output>

<result>63/10 = around 6.3</result>