A balloon at 25°C has 30 L. What will the balloon's volume at 35°C?
Answer using that method

The balloon's volume at 35°C : V₂=31.01 L
Given
T₁ = 25°C+273 = 298 K
V₁ = 30 L
T₂ = 35 °C + 273 = 308 K
Required
The new volume (V₂)
Solution
Charles's Law
When the gas pressure is kept constant, the gas volume is proportional to the temperature
[tex]\tt \dfrac{V_1}{T_1}=\dfrac{V_2}{T_2}[/tex]
Input the value :
V₂=(V₁.T₂)/T₁
V₂=(30 x 308)/298
V₂=31.01 L