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Required the interest of 316 dollars for 1 year and O months.
ll=half the number of
Ans. 3476cts.=$34, 76cts. 2. What is the interest of 364 dols. 25 cts. for 4 months ?
2 half the months.
Ans. 728, 50cts. =$7, 28cts. 5m.
JII. When the principal is given in federal money, at 6 per cent to find how much the monthly interest will be in New England, &c. currency.
RULE. Multiply the given principal by ,03 and the product will be the interest for one month, in shillings and decimal parts of a shilling.
1. What is the interest of 325 dols. for 11 months ?
9,75 shil. in for 1 month x11 months.
Ans. 107,258.=£5 7s. 3d. 2. What is the interest in New England currency, of 31 dots, 68 cts. for 5 months ?
Principal 31,68 dols.
,9504 Interest for one month.
Ans. 4,7520s=4s. 9d.
IV. When the principal is given in pounds, shillingu, &c. New-England currency, at 6 per cent. to find how much the monthly interest will be in Federal Money.
RULE. Multiply the pounds, &c. by 5, and divide that pro duct by 3, the quotient will be the interest for one month, in cents, and decimals of a cent, &c,
EXAMPLES: 1. A note for £411 New England currency has been on interest one month ; how much is the interest thereof in Federal Money?
Ans. 685cts. =$6, 85cts. 2. Required the interest of 391. 189. N. E. currency for my months ? £.
39,9 decimal value
Interest for 1 mo. 66,5 cents,
Ditto for 7 months, 465,5cls.=84 65cts. 5m. Ans.
· V. When the principal is given in New-England and Virginia currency, at 6 per cent. to find the interest for a year, in dollars, cents and mills, by inspection.
RULE. Since the interest of a year will be just so many cents as the given principal contains shillings, therefore, write down the shillings and call them cents, and the pence
in the principal made less by l if they exceed 3, or by 2 when they exceed 9, will be the mills, very nearly.
1. What is the interest of 21. 53. for a year at 6 per ct. 3
£2 58.5458. Interest 45cts. the Ansiper. 2. Required the interest of 100l. for a year at 6 per ct. ?
£100=2000s. Interest 2000 cts. $20. Ans. 8. Of 27s, 6d. for a year?
Ans. 278. is 27 cts, and 6d. is 5 mills. 4. Required the interest of 5l. 10s. 11d. for a year?
£5 108.=110s. Interest 110cts.= 1, 10cts. Om. 11 pence-2 per rule leaves =
VI. To compite the interest on any note or obligation, when there are payments in part, or indorsements.
RULE. 1. Find the amount of the whole principal for the whole time.
2. Cast the interest on the several payments from the time they were paid, to the time of settlement, and find their amount ; and lastly deduct the amount of the several payments, from the amount of the principal.
Suppose a bond or note dated April 17, 1793, was given for 675 dollars, interest at 6 per cent. and there were payments indorsed upon it as follows, viz.
First payment, 148 dollars, May 7, 1794.
Third payment, 99 dols. Jan. 2, 1798. I demand how much remains due on said note, the 17th of June, 1798 ?
184, 50 amount
341, 00 second payment, Aug. 17, 1796. Yr. mo. 37, 51 Interest to June 17, 1798 51 10.
378, 61 amounts
$219, 52 remains due on the note, June '17, 1798.
2. On the 16th of January, 1795, I lent James Pay* well 500 dollars, on interest at 6 per cent. which I receivá ed back in the following partial payments, as under, viz. 1st of April, 1796
$ 50 16th of July, 1797
400 1st of Sept. 1798
60 How stands the balance between us, on the 16th Noé vember, 1800 ?
Ans. due to me $63, 18cts. 3. A. PROMISSORY NOTE, viz. £62 10s. New-London, April 4, 1797. On demand I promise to pay Timothy Careful, sixty. two pounds, ten shillings, and interest at 6 per cent. per annum, till paid ; value received. John STANBY,
£. Íst. Received in part of the above note, September 4, 1799.
50 0 And payment June 4, 1800,
12 10 How much remains due on said note, the fourth day of December, 1800 ?
of 9. d. slne. 9 12 6
NOTE.--The preceding Rule, by custom is rendered so popular, and so much practised and esteemed by many on account of its being simple and concise, that I hove given it a place : il may answer for short periods of time, but in a long course of years, it will be found to be very erroneous.
Although this melhod seems at first view to be upon the ground of simple interest, yet upon a little attention the following objection will be found most clearly to lie against it, viz. that the interest will, in a course of years, completely expunge, or as it may be said, eat up the debt. For an explanation of this, take the following
A lends B 100 dollars, at 6 per cent. interest, and takes ħis note of hand; B does no more than pay A at every year's end 6 dollars, (wnich is then justly due to B for the use of his money) and has it endorsed on his note. At the end of 10 years B takes up his noie, and the sum he has to pay is reckoned thus : The principal, 100 dollars, on interest 10 years amounts to 160 dollars ; there are nine endorsements of 6 dollars each, upon which the debtor claims interest; one for nine years, the second for 8 years, the third for 7 years, and so down to the time of settlement; the whole amount of the several en. dorsements and their interests, (as any one can see by casting it) is $70, 20 cts. this subtracted from 160 dols. the amount of the debt, leaves in favour of the creditor, $89, 40 cts. or $10, 20 cts. less than the original principal, of which he has not received a cent, but only its annual interest.
If the same note should lie 20 years in the same way B would owe but 37 dols. 60 cts. without paying the least fraction of the 100 dollars borrowed.
Extend it to 28 years, and A the creditor would fall in debt to B, without receiving a cent of the 100 dollars which he lent him. See a better Rule in Simple Inter rest by decimals, page 175.