`W_(CH_(4))=3.2 g`
Moles of `CH_(4)=3.2/16=0.2`
`W_(CO_(2))=4.4 g`
Moles of `CO_(2)=4.4/44=0.1`
Total moles presnt in mixture `=0.2+0.1=0.3`
Volume of flask `=9 dm^(3)=9 L`
Temperature `=273+27=300 K`
Now for pressure of mixture `=PxxV=nRT`
`Pxx9=0.3xx0.821xx300`
`P=(0.3xx0.0821xx300)/9=0.821 atm`
`=0.821xx1.013xx10^(5) Pa=8.314xx10^(4) Pa`