Fertilizer weight

Fertilizer for gardeners contains the following trace elements:
bor. ... ..minimum 0.3promile weight. What is the smallest weight of each trace element in a five-kilogram fertilizer package?

Final Answer:

x =  1.5 g

Step-by-step explanation:

$$\begin{gathered} m=5\text{kg}\to \text{g}=5\cdot 1000\text{g}=5000\text{g} \\ r=0.3‰=\frac{0.3}{1000}=0.0003 \\ x=m\cdot r=5000\cdot 0.0003=1.5\text{g} \end{gathered}$$

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