A potion for spraying fruit trees, the mass ratio of pesticide to water is 1:150, there are 4 kg of pesticide, how many kg of this potion can be prepared.
一种喷洒果树的药水，农药和水的质量比是1：150，现有4千克农药，能配这种药水多少千克．
<gadget id="calculator">1 + 150</gadget>
<output>151</output>

<gadget id="calculator">1 / 151</gadget>
<output>1/151 = around 0.006623</output>

<gadget id="calculator">4 / (1/151)</gadget>
<output>604</output>

<result>604</result>