Answer
See the answer below.
Work Step by Step
a) Root mean square speed is inversely proportional to the molecular weight, so:
$NO_2\lt O_2\lt NO$
b) Since $P\propto n$:
$150\ mmHg/P_{O_2}=2/1$
$P_{O_2}=75\ mmHg$
c) Since $P\propto n$:
$150\ mmHg/P_{NO_2}=2/2$
$P_{NO_2}=150\ mmHg$
