48 people take a boat in the park, each small boat takes 3 people, the rent is 20 yuan, each big boat takes 5 people, the rent is 30 yuan, what is the minimum rent to be paid.
48人在公园坐船，每只小船坐3人，租金20元，每只大船坐5人，租金30元，最少要付租金多少元．
<gadget id="calculator">30 * 9</gadget>
<output>270</output>

<gadget id="calculator">3 / 3</gadget>
<output>1</output>

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

<gadget id="calculator">270 + 20</gadget>
<output>290</output>

<result>290</result>