A kind of medical alcohol is prepared with pure alcohol and water at a ratio of 3:1. There is 45 kg of pure alcohol. How much of this medical alcohol can be prepared.
一种医用酒精，用纯酒精和水按3：1配制而成，现有纯酒精45千克，可以配制多少的这种医用酒精．
<gadget id="calculator">3 + 1</gadget>
<output>4</output>

<gadget id="calculator">3 / 4</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">45 / (3/4)</gadget>
<output>60</output>

<result>60</result>