FEDERAL MONEY. II. To find the interest of any number of cents for any number of days less than a month, at 6. per cent. RULE. Multiply the cents by the number of days, divide the product by 6, and point off two figures to the right, and all the figures at the left hand of the dash, will be the interest in mills, nearly. EXAMPLES. Required the interest of 85 dollars, for 20 days. mills. Ans. 283 which is 28 cts. 3 mills. 2. What is the interest of 73 dollars 41 cents, or 7341 cents, for 27 days, at 6 per cent.? Ans. 350 mills, or 33 cts. III. When the principal is given in pounds, shillings, &c. New-England currency, to find the interest for any number of days, less than a month, in Federal Money. RULE. 1 Multiply the shillings in the principal by the number of days, and divide the product by 36, the quotient will be the interest in mills, for the given time, nearly, omitting fractions. EXAMPLE. Required the interest, in Federal Money, of 271. 15s. for 27 days, at 6 per cent. £. s. S. Ans. 27 15=555×27÷36=416 mills.-41cts. 6m. IV. When the principai is given in Federal Money, and you want the interest in shillings, pence, &c. NewEngland currency, for any number of days less than a month RULE. Multiply the principal, in cents, by the number of days, and point off five figures to the right hand of the product which will give the interest for the given time, in shil lings and decimals of a shilling, very nearly. EXAMPLES. A note for 65 dollars, 31 cents, has been on interest 25 days; how much is the interest thereof, in New-England currency? $ cts. S. s. d. grs. Ans. 65,31=6531×25=1,63275=1 7 2 REMARKS.-In the above, and likewise in the preceding practical Rules, (page 127) the interest is confined at six per cent. which admits of a variety of short methods of casting; and when the rate of interest is 7 per cent. as established in New-York, &c. you may first cast the interest at 6 per cent. and add thereto one sixth of itself, and the sum will be the interest at 7 per cent. which per haps, many times, will be found more convenient than the general rule of casting interest. EXAMPLE. Required the interest of 75l. for 5 months at 7 cent. S. 7,5 for 1 month. 5 £. s. d. 37,5=1 17 6 for 5 months at 6 per cent. Ans. £2 3 9 for ditto at 7 per cent. per A SHORT METHOD FOR FINDING THE REBATE OF ANY GIVEN SUM, FOR MONTHS AND DAYS. RULE. Diminish the interest of the given sum for the time by ts own interest, and this gives the Rebate very nearly. EXAMPLES. 1. What is the rebate of 50 dollars for six months, at 6 per cent. ? The interest of 50 dollars for 6 mouths, is 1 50 4 Ans. Rebate, $1 46 2. What is the rebate of 150l. for 7 months, at 5 per cent. ? s. d. 6 nterest of 150l. for 7 months, is 4 7 interest of 4l. 7s. 6d. for 7 months, is 2 61 Ans. £4 4 11 nearly. By the above Rule, those who use interest tables in their counting-houses, have only to deduct the interest of the interest, and the remainder is the discount. A concise Rule to reduce the currencies of the different States, where a dollar is an even number of shillings, to Federal Money. RULE I. Bring the given sum into a decimal expression by inspection, (as in Problem I. page 87) then divide the whole by,3 in New-England and by,4 in New-York currency, and the quotient will be dollars, cents, &c. EXAMPLES. 1. Reduce 541. 8s. Sid. New-England currency, to Federal Monev. ,3)54,415 decimally expressed. Ans. $181,38 cts. 2. Reduce 78. 11şd. New-England currency, to Federa. Monev. 7s. 114d.=0,399 then,,5),399 Ans. $1,53 3. Reduce 5131. 16s. 10d. New-York, &c. currency, to Federal Money. ,4)513.842 decimal Ans. $1284,60 4. Reduce 19s. 5d. New-York, &c. currency, to Federal Money. 10,974 decimal of 19s 5ąd. 82,435 Ans. 5. Reduce 641. New-England currency, to Federal Money. 64000 decimal expression. 213,354 Ans. NOTE-By the foregoing rule you may carry on the decimal to any degree of exactness; but in ordinary practice, the following Contraction may be useful. RULE II. To the shillings contained in the given sum, annex 8 times the given pence, increasing the product by 2: then divide the whole by the number of shillings contained in a dollar, and the quotient will be cents. EXAMPLES. 1. Reduce 45s. 6d. New-England currency, to Federal Money. - 50 to be annexed, 6x8+2 87,583 Ans. 758 cents.,38 .. Reduce 2. 10s. 9d. New-York, &c. currency, to Federal Money. 9x8+2=74 to be annexed. Or thus, 8)50,74 Then 8)5074 $ cts. N. B. When there are no pence in the given sum, you must annex two cyphers to the shillings; then divide as before, &c. 3. Reduce 31. 5s. New-England currency, to Federal money. 31. 58.652. Then 6)6500 ns. 1083 cents. SOME USEFUL RULES, FOR FINDING THE CONTENTS OF SUPERFICIES AND SOLIDS. SECTION I. OF SUPERFICIES. The superficies or area of any plane surface, is composed or made up of squares, either greater or less, according to the different measures by which the dimensions of the figure are taken or measured :-and because 12 inches in length make 1 foot of long measure, there fore, 12×12=144, the square inches in a superficial foot, &c. ART. I. To find the area of a square having equal sides. RULE. Multiply the side of the square into itself, and the product will be the area, or content. EXAMPLES. 1. How many square feet of boards are contained in the floor of a room which is 20 feet square? 20×20=400 feet, the Answer. 2. Suppose a square lot of land measures 26 rods on each side, how many acres doth it contain? NOTE.-160 square rods make an acre. Therefore, 26×26=676 sq. rods, and 676÷160=4&. 36r. the Answer. ART. 2. To measure a parallelogram, or long square. RÜLE. Multiply the length by the breadth, and the product will be the area, or superficial content. EXAMPLES. 1. A certain garden, in form of a long square, is 96 ft. ong, and 54 wide; how many square feet of ground are contained in it ? Ans. 96x54-5144 square feet. 2. A lot of land, in form of a long square, is 120 rods in length, and 60 rods wide; how many acres are in it? 120×60 7200 sqr. rods, then 1200=45 acres. Ans. 3. If a board or plank be 21 feet long, and 18 inches Droad; how many square feet are contained in it? 18 inches=1,5 feet, then 21×1,5=81,5 Ans. |