Aweather balloon is inflated to a volume of 27.6 l at a pressure of 736 mmhg and a temperature of 26.1 âc. the balloon rises in the atmosphere to an altitude where the pressure is 360. mmhg and the temperature is -14.0 âc.

We know from gas equation: 

PV=mRT

Where:
P is pressure
V is the volume of the balloon
m is the mass of gas in the balloon (constant)
R is universal gas constant divided by mean molar wt of air (about 28 g/mol) T is thermodynamic temperature (T in Kelvin; T=273 + t (in deg C)
P1 * V1 =m*R*T1 (i) P2 * V2 =m*R*T2 (ii)
Dividing 1 by 2 we get: 
V1 / V2 = (P2/P1) * (T1/T2)
Given:V1=27.6, P1=736mmhg, T1 = 273+26.1=299.1V2=?, P2 = 360mmhg, T2 = 273+(-14)=259
so, V2 = 27.6*(736/360)*(259/299.1) = 48.86