Teacher Wang goes to the store to buy sporting goods. If she only buys volleyballs with the money, she can buy 18. If she buys all basketballs, she can buy 12. It is known that a volleyball is 20 yuan cheaper than a basketball. How much money did Teacher Wang bring?
王老师去商店买体育用品，她带的钱如果只买排球正好买18个，如果全部买篮球正好买12个，已知一个排球比一个篮球便宜20元，王老师带了多少钱？
<gadget id="calculator">1 / 12</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">1 / 18</gadget>
<output>1/18 = around 0.055556</output>

<gadget id="calculator">(1/12) - (1/18)</gadget>
<output>1/36 = around 0.027778</output>

<gadget id="calculator">20 / (1/36)</gadget>
<output>720</output>

<result>720</result>