Teacher Wang buys volleyballs and footballs, and the number of volleyballs purchased is (1/3) of the number of footballs. If 10 volleyballs are replaced by 10 footballs, then the number of volleyballs is only equivalent to (1/7) of footballs. How many volleyballs and footballs did Mr. Wang buy?
王老师购买排球和足球，其中购买的排球个数是足球个数的(1/3)，如果把10个排球换成10个足球，那么排球的只数相当于足球的(1/7)，问王老师买来的排球和足球共有多少个？
<gadget id="calculator">1 / 7</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">10 * (1/7)</gadget>
<output>10/7 = around 1.428571</output>

<gadget id="calculator">10 + (10/7)</gadget>
<output>80/7 = around 11.428571</output>

<gadget id="calculator">3 * (1/7)</gadget>
<output>3/7 = around 0.428571</output>

<gadget id="calculator">1 - (3/7)</gadget>
<output>4/7 = around 0.571429</output>

<gadget id="calculator">(80/7) / (4/7)</gadget>
<output>20</output>

<gadget id="calculator">20 * 3</gadget>
<output>60</output>

<gadget id="calculator">20 + 60</gadget>
<output>80</output>

<result>80</result>