Question 363931
Both of these formulas are for computed compounded interest.  {{{A=P(1+r/n )^nt }}} will approach the formula {{{A=pe^rt}}} in the limit as n approaches infintity.  In other words limit as n-->infinity {{{(1+r/n )^n =e^r}}}
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n = number of periods to compound, P is the principal invested, r=annual rate and t=number of years.  
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In your case n=1 since you are compounding once a year and therefore you need to use the formula {{{A=P(1+r/n )^nt }}}.   The other formula would only be valid if you were compounding over very granular periods (ie days or hours) or n is very large.
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given
n=1 compounded annually, p=850, r=4% or 0.04 and t=17
 
{{{A=P(1+r/n )^(nt) }}}={{{850*(1+(.04/1))^(1*17)=850*(1.04)^17=1655.72   }}}