Gas Laws: Pressure and Volume Changes in a Rising Weather Balloon

A weather balloon is released at ground level where the pressure is 1.00 atm and the temperature is 300 K. As it rises to a higher altitude, the pressure drops to 0.60 atm and the temperature decreases to 270 K. If the initial volume of the balloon is 2.0 L, what will be its new volume? Use the combined gas law: $\frac{P_1 V_1}{T_1} = \frac{P_2 V_2}{T_2}$.

Which of the following best describes what happens to the pressure and volume of a weather balloon as it rises through the atmosphere, assuming temperature decreases slightly?

If a weather balloon at sea level has a volume of 5.0 L at a pressure of 1.00 atm and a temperature of 298 K, what will its volume be at a pressure of 0.50 atm and a temperature of 273 K? Use $\frac{P_1 V_1}{T_1} = \frac{P_2 V_2}{T_2}$.