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
True cus i don’t remember but it’s true
The answer to the question is 90
I also think the answer is D, who else agrees with me? Btw, thank you for posting this question. I enjoy answering fun things sometimes.