3. 2789 fr. 50c. - 2400 fr. .. simple int. for 1 yr. on

389 fr. 50c.;

=

2400 fr. =389.5÷3=114 fr.; .. 2400 fr.: 100 fr. :: 114fr.: rate of int. required;

.. rate of int. required=

114 × 100

2400

fr.=43 fr.

4. Int. on £100 at 3 per cent. for 5 yrs. = £17. 10s. ;
£117. 10s.: £1884. 19s. 104d. :: £100 prin. required,
or 112800g.: 180959400g. :: £i00: principal required;
180959400
1128

.. principal required = £

= = £1604. 5s.

5. £4127. 10s.: £100 :: £92. 17s. 44d. : rate per cent,

£4127: £100 :: £92117: rate per cent;

6. 100 francs in 3 years at 4 per cent. amount to 114 francs, 114 fr.: 3357-3 fr.: 100 fr.: principal required;

.. principal required=

335730
114

-fr.=2945 fr.

COMPOUND INTEREST.-Ex. IX. Page 48.

.. £840+£42, or £882-prin. for 2nd year.

£

882

5

£44.10

20

2.00s.

.. £882+£44. 2s., or £926. 2s.=prin. for 3rd year.

£ S. 926 2

£46.30 10

20

6.10s.

12

1.20d.

.. compound int. = £42+ £44. 2s. + £46. 6s. 1}d. = £132. 8s. 1d. Amount = £840+£132. 8s. 1d. = £972. 8s. 1zd.

9.559096875 int. for 2nd year.
9.34875 int. for 1st year.

£18.907846875 compound int. for 2 years.

20

18.156937500s.

12

1.883250000d.

.. compound int. = £18. 18s. 1.88325d.

Amount £415. 10s. + £18. 18s. 1-88325d. =£434. 8s. 1.88325d.

5th

=155.7504

-161.980416

=168 45963264

compound int.=779.95044864

=779 fr. 95 c. nearly;

... amount=3600 fr. +779 fr. 95 c. nearly =4379 fr. 95c, nearly.

(4) £330. 3s. 7дd.= £330·18125.

£ 330-18125

3

£9.9054375 int. for 1st year. 330.18125

£340 0866875 prin. for 2nd year.

3

£10.202600625 int. for 2nd year.
340-0866875

£350 289288125 prin. for 3rd year.

3

£10.50867864375 int. for 3rd year.

Amount = £330. 3s. 74d. + £30. 12s. 4d. nearly = £360. 15s. 111⁄2d. nearly. ́

(5) £1321. 16s. 10d.= £1321-84166666...

.. compound interest £101. 128. 8d. nearly.

=

Amount = £1321. 16s. 10d. + £101. 12s. 8d. nearly =£1423. 9s. 6d. nearly.

Compound interest = £270. 12s. 1d. nearly £250 · =£20. 12s. 1 d. nearly.