MATHEMATICAL PAPERS. 8r 
cent. is the intereft at 12 per cent.—If to that double there 
be added one fixth of the intereft at 6 per cent. the fum will 
be the intereft at 13 per cent. &c. 2 
And this divifion, addition or fubtraction may be Mp im- 
mediately after the firft operation of multiplying the money at 
intereft by half the time, or 2contra, and before the ar 
the figures into pounds and decimals.. | 
Example. Let there be computed the intereft of fj: jf, 
for 7 months and 15 days, at 5 per cent. per annum. 
M. 
£-480, 7, 50 
$75. C 
"PERI 39 75 
2400 
3360 
1440 
180000 at 6 per cent. 
30000 $ deduct. 
15,0000 at's per cent. . 
Anf. £.15; 
Example. Let the intereft of £.345 158. for 9 months and. 
6 days, be computed, at the rate of 7 per cent. per annum. 
£ DLL MON uA 
ld half the time. 
2074500 
138300 
15904500 at 6 per cent. 
2650750 $ add. 
18,565250 at 7 per cent. 
20 
11,305000 
12. 
3,660000 
4 
2, 
Anf. £.18 11s. 3d. 29. Let 
