Parameterize this surface (call it
) by

with
and
. Take the normal vector to
to be

Then the area of
is



4x-20+=-4
-4 -4
x-20=-8
+20 +20
x=12.
If one package of hot dogs buns is 12 than she need 2 packages
The probability of there being zero males is given by:

Similarly the probability of there being zero females is also 1/16.
The probability there will be at least 1 male and 1 female is therefore:

The answer is: 7/8.