two 4 pences, or 8d, in the price; and the sum £ 159 .. 1 .. 8 will be the value required. Required the price of 36 tuns 15cwt. 3qrs. of sugar at 2d. OF DEDUCTIONS ON WEIGHT, &c. When goods or merchandize are weighed in the box, cask or other package, the amount is called the Gross weight: and proper allowances being made for these packages, the remainder is called the neat or nett weight: this allowance is called the Tare, and is usually calculated at the rate of so much on the 100lbr. Tret is another kind of allowance, granted on certain goods which are liable to lose their weight or measure by keeping, that it may be complete when the goods are resold. Draught is also an allowance granted to turn the scale in favour of the purchaser. All these allowances are computed as in the following examples: Required the nett weight of 26cwt. 3qrs. 16lbr. allowance for tare being made at 16lbr, per cwt. As take the seventh part of the gross weight 26cwt. 3qrs. 16lbr., which is 3cwt. 3qrs. 10lbr. 44 ounces for the Tare, and subtracting this quantity from the gross weight we have 23cwt. Oqrs. 5lbr. 1130z. for the nett weight. Again, required the Tret upon 36cwt. 1qr. 18lbr. at 4lbr. on the 104lbr. In this case the rate of Tret being as 4lbr. to 104lbr. we multiply the gross weight by 4, and divide the product by 104 to have the quantity to be allowed: but as 4 is the 26th part of 104, the same result may be obtained more speedily by dividing the given gross weight at once by 26. OF INTEREST. By interest is meant the allowance made by the borrower of a sum of money to the lender, for the use of that money, and it is computed at the rate of so much for the 100, for a whole year. The highest rate allowed by the Laws of this country is £5, for £100, per annum, and proportionally for any other sum, and for any other period of time. The Interest may therefore be calculated by Simple or compound Proportion, in the manner already shown: but for practice shorter methods are convenient, such as to divide the given principal by the number expressing what part of £ 100 is the given interest; for instance, in computing the interest of any sum at £5 on 100, or, as it is usually written and expressed, 5 per centum, we have only to divide the principal by 20, because 5 is the twentieth part of 100. In the same way for 4 per cent. we divide the principal by 25, because 25 times 4 are 100. Example. What is the interest of £768.. 13.. 4, for 1 year, at 5 per centum ? .. Working first by the rule of Proportion we say, if 100 gain 5, in a given time, what will £ 768 .. 13.. 4 gain in the same time; and the result is £ 38 .. 8 8: but as 5 is the twentieth part of 100, the operation will be abridged by merely taking the twentieth part of the principal, as here shown, and the same result will be obtained. Again, required the interest of £365, for 3 months, at 4 per cent. £ £ Sh. £ 100: 4 10 :: 365 20 - 90 365 £ Sh. d. 100)32 850(16.. 8 .. 6. Interest for 12 months 16.8 12 4..2.. 14 Interest for 3 months. Here the proportion is as 100 to £4. 10, (equal to 4 per cent.) so 365 to a fourth proportional; the middle term being reduced to shillings is multiplied by the given principal and the product is divided by 100, producing the sum £ 16 .. 8 .. 6, as the interest for 1 year or 12 months; of which the fourth part £4 2.. 1 is the interest for 3 months, as required. At 4 per cent. required the interest of £ 5683.. 12, for the months of May, June, July and August. Here 4 being the twenty-fifth part of 100, we divide the given principal by 25, and obtain the interest for a whole year, or 365 days; but as the given months contain only 123 days, we multiply this interest by 123 and divide the product by 365, whence we have £76.. 12.. 2 for the interest required. |