235 19 1 
* 
the rate in- 
ernment scale 
nnuities. 
perpetuity, 
i + O"* 
i 
than any 
nishes, and 
the interest 
£434 per 
.05 
46.25 “ ¿+6 5 0 
58. To find (0 the interest— 
(Art. 5+) a — ip, , 
dividing by p. 
100 i = 
a 
P ~ 
100 a 
V 
, interest of £1 per annum 
ditto per cent. 
Rule. Multiply the annuity by 100, and divide by the principal, 
which gives the rate per cent. 
What rate per cent is obtained when .£925 secures a perpetuity of 
£46 5 per annum? 
p — 925 
= 46.25 
100 
925)4625(5 per cent. 
4625 
When the annuity is payable m! times in a year, and interest is con 
vertible m times, ( 1 —(— ■ 
vanishes in the formula of Art. 55., 
when the annuity is perpetual, and the expression then becomes