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Question 37921:  Please help I am stuck on this problem :(
 
3)	The formula for calculating the amount of money returned for deposit money into a bank account or CD (Certificate of Deposit) is given by the following: 
A=P (1 + r/n)^(nt) 
  
A is the amount of returned 
P is the principal amount deposited 
r is the annual interest rate (expressed as a decimal) 
n is the compound period 
t is the number of years
 
Suppose you deposit $20,000 for 3 years at a rate of 8%. 
a)	Calculate the return (A) if the bank compounds annually (n = 1). 
Answer:   
Show work in this space. Use ^ to indicate the power.  
 
 
 
 
b)	Calculate the return (A) if the bank compounds quarterly (n = 4), and carry all calculations to 7 significant figures. 
Answer:   
Show work in this space .  
 
 
 
c)	Calculate the return (A) if the bank compounds monthly (n = 12), and carry all calculations to 7 significant figures. 
Answer:   
Show work in this space.   
 
 
 
 
d)	Calculate the return (A) if the bank compounds daily (n = 365), and carry all calculations to 7 significant figures. 
Answer:   
Show work in this space.  
 
 
 
 
e)	What observation can you make about the increase in your return as your compounding increases more frequently?  
Answer:  
 
 
 
f)	If a bank compounds continuous, then the formula becomes simpler, that is  
 where e is a constant and equals approximately 2.7183. Calculate A with continuous compounding.  
Answer:   
Show work in this space  
 
 
 
 
g)	Now suppose, instead of knowing t, we know that the bank returned to us $25,000 with the bank compounding continuously. Using logarithms, find how long we left the money in the bank (find t).  
Answer:   
Show work in this space  
 
 
 
h)	A commonly asked question is, “How long will it take to double my money?” At 8% interest rate and continuous compounding, what is the answer?  
Answer:  Show work in this space 
 Answer by stanbon(75887)      (Show Source): 
You can  put this solution on YOUR website! Suppose you deposit $20,000 for 3 years at a rate of 8%. 
a) Calculate the return (A) if the bank compounds annually (n = 1). 
Answer:  
Show work in this space. Use ^ to indicate the power.
 
A=20,000(1+0.08/1)^(1)=21600 
 
 
 
b) Calculate the return (A) if the bank compounds quarterly (n = 4), and carry all calculations to 7 significant figures. 
Answer:  
Show work in this space .
 
A=20000(1+0.08/4)^4=27209.78 
 
 
 
 
c) Calculate the return (A) if the bank compounds monthly (n = 12), and carry all calculations to 7 significant figures. 
Answer:  
Show work in this space. 
 
A=20000(1+0.08/12)^12=21659.99
 
d) Calculate the return (A) if the bank compounds daily (n = 365), and carry all calculations to 7 significant figures. 
Answer:  
Show work in this space. 
 
A=20000(1+0.08/365)^365=21665.55
 
e) What observation can you make about the increase in your return as your compounding increases more frequently?  
Answer: 
 
A increases as compounding times increases.
 
f) If a bank compounds continuous, then the formula becomes simpler, that is  
where e is a constant and equals approximately 2.7183. Calculate A with continuous compounding.  
Answer:  
Show work in this space 
 
A=e^(rt)
 
g) Now suppose, instead of knowing t, we know that the bank returned to us $25,000 with the bank compounding continuously. Using logarithms, find how long we left the money in the bank (find t).  
Answer:  
Show work in this space 
 
25000=20000e^(0.08t) 
1.25=e^(0.08t) 
Take the natural log of both sides to get: 
ln(1.25)=0.08t 
0.223/0.08=t 
t=2.789
 
 
 
h) A commonly asked question is, “How long will it take to double my money?” At 8% interest rate and continuous compounding, what is the answer?  
Answer: Show work in this space
 
40000=20000e^0.08t 
2=e^0.08t 
Take the natural log of both sides to get: 
0.6931...=0.08t 
t=8.66 yrs.
 
Cheers, 
Stan H. 
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