(1 + *')■ 
(1 + iy 
Rule. Multiply the present value by the interest of £l for a year, 
and divide the product by the difference between unity and the present 
value of £l, due the same number of years the annuity has to continue. 
Or by the Tables— 
Divide the purchase money by the present value of £l per annum, 
given in the Tables. 
Example. What annuity, to continue 20 years, may be purchased 
for £500 when the interest of money is 4 per cent ? 
By Table 6, 13.590326 is the present value of £l per annum for 
20 years. 
13.590326)500 (36.791 = £36 15 10 
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