Answer:
83.65°C
Step-by-step explanation:
Step one:
given data
V1=1.80L
T1=20°C
P1=1atm
V2=1.55L
T2=? new temperature
P2=0.667atm
Step two:
The combined gas equation is given as
P1V1/T1=P2V2/T2
make T2 which is the new temperature subject of formula we have
T2=(P2*V2*T1)/P1
T2=1.8*1.55*20/0.667
T2=55.8/0.667
T2=83.65°C
Therefore the new temperature is 83.65°C when the balloon rises 3km