Answer
a) 624 Pa
b) 1,249 Pa
Work Step by Step
a) We use the equation for pressure to find:
$P =\frac{F}{A}=\frac{mg}{4\pi r^2} = \frac{(.05)(9.81)}{4\pi (.005)^2} =624 \ Pa$
b) We use a similar process, now considering the mass of the water and the oil, to find:
$P =\frac{F}{A}=\frac{mg}{4\pi r^2} = \frac{(.1)(9.81)}{4\pi (.005)^2} =1249 \ Pa$