A car wash shop pays 200 yuan for 10 car washes in cash, but only 150 yuan for 10 car washes with a car wash card. How much cheaper is it to wash a car with a car wash card than to pay cash?
某洗车店付现金洗车10次需要200元，如果使用洗车卡，10次只需要150元．使用洗车卡洗车比付现金洗车每次便宜多少元？
<gadget id="calculator">200 / 10</gadget>
<output>20</output>

<gadget id="calculator">150 / 10</gadget>
<output>15</output>

<gadget id="calculator">20 - 15</gadget>
<output>5</output>

<result>5</result>