Dear student
Molar mass of
" " "
When they are present in the ratio a:b , their average molecular mass = (EQUATION 1)
16a+28b = 20(a+b) ; 4a+ 7b= 5(a+b)
a=2b or a:b=2:1
If the ratio is reversed , now the ratio a: b= 1:2
USING EQUATION 1,
Average molar mass=
Regards