Fie raportul molar etan:propan=x:y
n=m/M => m=n*M
M etan=30g/mol si Mpropan=44g/mol
m etan=30x si mpropan=44y
30x+44y.............100%
6x+8y...............18,75%
600x+800y=562,5x+825y
37,5x=25y => y=1,5x
m etan=30x si mpropan=66x
mamestec=96x
%etan=m etan*100/mamestec=31,25%
%propan=mpropan*100/mamestec=66*100/96=68,75%