If a zero-coupon bond can be redeemed in 20 years for $10,000:
 a.) If 10% compounded monthly:
  
 10,000 = P {1 + (.10 / 12)}^(12)(20) / P {1 + (.10 / 12)}^(12)(20) / P {1 + (.10 / 12)}^(12)(20) 
 = 7.328073633249730071995931977855 / 7.328073633249730071995931977855 / 7.328073633249730071995931977855
 = 0.13646151090276871636035564271905
 = 10,000 * 0.13646151090276871636035564271905
 = 1364.6151090276871636035564271905
 P = $1364.62
 You should be willing to pay $1364.62 for it now if you want a return of 10% compounded monthly.
  
 b.) If 10% compounded continuously:
 A = Pe^rt
 10,000 = Pe^(10)(20) / e^(10)(20) / e^(10)(20)
 $1353.35 = P
 You should be willing to pay $1353.35 for it now if you want a return of 10% compounded continuously.