Temperature 36991

Honza filled 2 liters of hot water at a temperature of 90 °C from a heater into a five-liter container. What temperature must the water that the container fills have a mixture temperature of 42 °C?

Correct answer:

t₂ =  10 °C

Step-by-step explanation:

$$\begin{gathered} V_1=2\text{l} \\ {V}_2=5-V_1=5-2=3\text{l} \\ {t}_1=90\text{°C} \\ t=42\text{°C} \\ (V_1+V_2)\cdot t=V_1\cdot t_1+V_2\cdot t_2 \\ (2+3)\cdot 42=2\cdot 90+3\cdot t_2 \\ 3t_2=30 \\ {t}_2=\frac{30}{3}=10 \\ {t}_2=10=10\text{°C} \end{gathered}$$

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