Chapter 5 - The Gaseous State - Questions and Problems - Page 221: 5.83

Please see the work below.

We know that $P_{O_2}=\frac{3.219\times 10^{-5}\times 0.08206\times 288}{0.2000}=0.003804atm$ $P_{He}=\frac{1.40\times 10^{-4}\times 0.08206\times 288}{0.2000}=0.01654atm He$ $P=P_{O_2}+P_{He}=0.003804+0.01654=0.0203atm$