Three examples per-mille

A. Calculate 1.5 ‰ from 4.5 liters of blood. Express the result in milliliters.
B. Calculate three ‰ from € 50,000.
C. The tray they brought breakfast to the landlord's bed is made of an alloy that contains 830 ‰ of silver. How much silver did they use on it if the tray weighed 390 g?

Correct answer:

a =  6.75 ml
b =  150 €
c =  323.7 g

Step-by-step explanation:

$$\begin{gathered} V=4.5\text{l}\to \text{ml}=4.5\cdot 1000\text{ml}=4500\text{ml} \\ {q}_1=1.5‰=\frac{1.5}{1000}=0.0015 \\ a=q_1\cdot V=0.0015\cdot 4500=6.75\text{ml} \end{gathered}$$

$$\begin{gathered} q_2=3‰=\frac{3}{1000}=0.003 \\ b=q_2\cdot 50000=0.003\cdot 50000=150\text{Eur} \end{gathered}$$

$$\begin{gathered} q_3=830‰=\frac{830}{1000}=\frac{83}{100}=0.83 \\ {m}_3=390\text{g} \\ c=q_3\cdot m_3=0.83\cdot 390=323.7\text{g} \end{gathered}$$

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