The correct answer is 41.
Vbox-vspheres
vbox=, I assume we are dealing with l=w=h
so
v=lwh=12^3=1728
vsphere=(4/3)pir^3
r=3
vsphere=(4/3)pi3^3=4pi9=36pi
8 of them so
8 times 36pi=288pi or about 904.7786842338604526772412943845 cubic inches
vbox-sphere=1728-904.7786842338604526772412943845=823.2213157661395473227587056155
space filled by packing beads is about 823.22 cubic inches
beads percent is 823.2213157661395473227587056155/1728 times 100=47.64% filled by beads
The effective rate is calculated in the following way:

where r is the effective annual rate, i the interest rate, and n the number of compounding periods per year (for example, 12 for monthly compounding).
our compounding period is 2 since the bank pays us semiannually(two times per year) and our interest rate is 8%
so lets plug in numbers:
Given:

First, let us find two points from this equation.
We can set values of x and then solve for y.
Let us find the values of y when x = 1, 2, 3, 4, 5

We now have a set of points:
(1, 21)
(2, 16)
(3, 11)
(4, 6)
(5, 1)
Since the given plane is limited to values of 10 and -10, the points that we can plot are the points (4, 6) and (5, 1)
The graph would then look like this: