Blueberries

Adéla sells blueberries for 50 CZK/1 l, and Zdeněk sells 1 kg of blueberries for 75 CZK. Which of them sells irritants if 1 liter of blueberries weighs 650 g?

Correct answer:

x = A

Step-by-step explanation:

$$\begin{gathered} m=650\text{g}\to \text{kg}=650:1000\text{kg}=0.65\text{kg} \\ q=1/m=1/0.65=\frac{20}{13}=1\frac{7}{13}\doteq 1.5385\text{l/kg} \\ {c}_1=50\cdot q=50\cdot 1.5385=\frac{1000}{13}=76\frac{12}{13}\doteq 76.9231\text{Kc/kg} \\ {c}_2=75\text{Kc/kg} \\ {c}_1>c_2 \\ x=A \end{gathered}$$

Try another example