Dongfeng Steel Rolling Plant rolled 94.5 tons of steel in 4.5 hours. According to this calculation, how many hours would it take to roll 50.4 tons of steel?
东风轧钢厂，4.5小时轧钢94.5吨，照这样算，轧50.4吨的钢，需要多少小时？
<gadget id="calculator">94.5 / 4.5</gadget>
<output>21</output>

<gadget id="calculator">50.4 / 21</gadget>
<output>2.4</output>

<result>2.4</result>