Question 1193477:  Suppose you want to have $400,000 for retirement in 20 years. Your account earns 5% interest compounded monthly.
 
a) How much would you need to deposit in the account each month?
 
$
 
 
b) How much interest will you earn?
 
$ 
 
 Answer by Boreal(15235)      (Show Source): 
You can  put this solution on YOUR website! P=d(1+(r/k))^nk -1)/(r/k) 
multiply through by (r/k)=0.05/12; P=400,000 
1666.67=d{(1.00416667)^240-1}=d=1.7126, round at the end 
d=$973.16 
the 240 payments of this over 20 years are $233,558.40 
the interest is the difference between that and $400,000=$166,441.60
 
 
  | 
 
  
 
 |   
 
 |