The physical education teacher brought some money to the store to buy table tennis rackets. If he bought 4 sets, he would still have 5 yuan left; if he bought 5 sets, he would be short of 15 yuan. How much did the physical education teacher bring?
体育老师带了一些钱去商店买乒乓球拍，如果买4副还余5元；如果买5副则缺15元，体育老师带了多少元钱？
<gadget id="calculator">5 + 15</gadget>
<output>20</output>

<gadget id="calculator">5 - 4</gadget>
<output>1</output>

<gadget id="calculator">20 / 1</gadget>
<output>20</output>

<gadget id="calculator">20 * 4</gadget>
<output>80</output>

<gadget id="calculator">80 + 5</gadget>
<output>85</output>

<result>85</result>