11. What is the interest on $1000 from February 20th, 1850, to November 15th, 1853, at 5 per cent. ? The interval of time between these dates would be found by the method explained in Polynomial Subtraction (124); but in calculations like the present it is customary to consider every month as containing 30 days. February being the 2d, and November the 11th month, we denote them by these numbers respectively; then subtracting polynomially, we find the interval of time to be 3y. 8m. 25da. Ans. $186.80'. 12. What is the interest on $350.90 from January 10th, 1850, to June 1st, 1852, at 6 per cent. ? Ans. $50.354'. 13. What is the interest on $425.30 from March 4th, 1851, to May 19th, 1853, at 7 per cent.? Ans. $65.744'. 14. What is the interest on $504.12 from September 12th, 1850, to February 3d, 1853, at 8 per cent.? Ans. $96.455'. 15. What is the interest on $634.25 from August 13th, 1850, to July 10th, 1854, at 10 per cent. ? Ans. $247.88'. 16. What is the interest on $730.37 from April 10th, 1852, to October 5th, 1855, at 12 per cent. ? Ans. $305.53'. (177.) Concise Method of computing Interest for Months and Days-allowing 12 months of 30 days each to a year. 1. For 6 per cent.-Multiply the Principal by half the number of months, and divide the product by 100; or multiply by of the number of days, and divide by 1000. 2. For any other rate-find the interest for 6 per cent., as above, and increase or diminish it proportionably for the other rate. EXAMPLES. 1. To find the interest of $50.10 for 8m. at 6 per cent. The interest of $1 for one year is 100; for 8m. it is therefore the numerator 4 being the number of months; and the given Principal X6, the interest of $1, gives the interest of that principal. 2. To find the interest of $500.10 for 18 days, at 6 per cent. $500.103-$1.50030. The interest of $1 for 1y. is Too; for 18da. it is therefore 6×18 =38x1000 of 1080T000, 1 the numerator 3 being of the number of days; and the 3 given Principal X TOO, the interest of $1, gives the interest of that principal. Having found the Interest at 6 per cent., of that would be the interest at 5 per cent.; % of it would be the interest at 7 per cent.; and so on. When the time is in months and days, find the interest for each, separately, and add the two results together, for the whole interest. When of the given number of days cannot be exactly expressed in integers and decimals, as of 20 days; it will be best to multiply the Principal by the whole number of days, and then divide the product by 6000. The remarks respecting the accuracy of the result which accompany the Example to Rule XLII., are also applicable to the present method. 17. Find the interest on $230 for 11m. 15da., at 6 per Ans. $13.225. cent. 18. Find the interest on $1234.75 for 120da., at 6 per Ans. $24.695. cent. 19. Find the interest on $4360.12 for 54da., at 5 per cent. Ans. 32.70'. 20. Find the interest on $1385.50 for 23da., at 7 per cent. Ans. $6.196'. 21. Find the interest on $2360.25 for 7m., at 8 per cent. Ans. $110.145. 22. Find the interest on $3879.061 for 9da., at 7 per cent. Ans. $6.788'. 23. Find the interest on $9000.87 for 17m., at 7 per cent. Ans. $892.586'. 24. Find the interest on $2300.25 for 137da., at 5 per cent. Ans. $43.768'. 25. Find the interest on $8730.621 for 5m. 23da., at 6 per cent., and also at 8 per cent. Ans. $251.73'; $335.64'. Partial Payments on Notes or Bonds. (178.) No one method has been universally approved for computing the Balance due on Notes, &c., bearing interest, on which partial payments have been made.· The following has been adopted by the Supreme Court of the United States, and by most of the individual States. 1. Whenever a payment, or the aggregate of payments made, will cancel the interest due, add the interest to the Principal, and from the amount subtract the payment, or aggregate of payments up to that time. 2. The remainder is to be regarded as a new Principal, dating from the time of the last payment; and payments on this principal are to be subtracted in the same manner as before; and so on. $4000. EXAMPLE. Washington, Jan. 1st, 1850. On demand I promise to pay James Wealthy, Four thousand dollars, with interest, for value received. John Ready. On this Note the following payments are endorsed: July 1st, 1851, received $300; April 11th, 1853, received $700. What balance is due on the Note on the 20th of August, 1855? The legal rate of Interest at Washington, D. C., is 6 per cent. (173). This is therefore the rate of interest which must be allowed on the Note, the debt being supposed to have been contracted in Washington; and the calculation for the Balance is as follows: The payment $300 will not cancel this interest. $4000.00 $360 786.66 Subtract the payments made, $300+700, 1000.00 The intervals of time between the dates will be found as in Ex. 11th, page 215. Interest for months and days may be computed by the general Rule (176), or, sometimes more concisely, by the other method (177). $950. Philadelphia, June 26th, 1853. On demand I promise to pay Timothy Friend, Nine hundred and fifty dollars, with interest, for value received. Jacob Faithful. Endorsements.-March 20th, 1854, received $430. May 15th, 1854, received $234.75. What balance was due, June 1st, 1855? Ans. $353.01'. $3000. New York, May 1st, 1852. 27. On demand I promise to pay to John Prosperous, Three thousand dollars, with interest, for value received. William Needy. Endorsements.-November 1st, 1852, received $1000, December 20th, 1854, received $300.50. What balance was due, January 1st, 1855? Ans. $2029.83'. |