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| 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
 
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