Answer:
Penny would need to put in ~ $18,181.82
Step-by-step explanation:
Using the equation 
Where A = the total
P is equal to the starting amount
r is equal to the rate (percent)
and t is equal to the total time.
We can put in:
A = $40,000
r = 0.08 (8%)
t = 15

Round to the nearest whole cent
P = $18,181.82
Answer:
790 for surface area
1800 for volume
Step-by-step explanation:
I believe this would be 51
To simplify begin by distributing the multiplication outside the parenthesis: