121. At what rate per cent. a year will $352 amount to $512.16 in 6 years and 6 months? Ans. 7 per cent. (3.) 122. At what rate will $600 amount to $856.50 in 9 years and 6 months? Ans. 4 per cent. (0.) 123. At what rate per cent. a year will $264 amount to $281.60 in 1 year and 3 months? Ans. 5 per cent. (0.) 124. At what rate per cent. a year will $89.10 amount to $108.90 in 3 years and 4 months? Ans. 63 per cent. (0.) 125. At what rate per cent. a year will $197.60 amount to $222.30 in 15 months? 126. At what rate will $648 years and 9 months? Ans. 10 per cent. (0.) amount to $1012.50 in 6 Ans. 8 per cent. (3.) 127. At what rate per cent, a year will $1200 amount to $1740 in 7 years and 6 months? Ans. 6 per cent. (0.) 128. At what rate per cent. a year will $340.80 amount to 589.30 in 9 years and 4 months? Ans. 718 per cent. (8.) 129. In what time will $500 amount to $860 at 6 per cent. a year? yr. $00 100 In this question, time is required as the answer, and we have 1 year, $100 principal, (since per cent. means for 100,) and $6 interest, $500 principal, and $360 interest, from which to make a statement that will give the time required; then we write 1 year on the right, at the head of the line, and observe, 1 year is the time required by the question, for $100 to gain interest, (no matter what sum,) and $500 will require less time to gain a like sum, hence the less of those two numbers is placed on the right of the line; again 1 year is the time required to gain $6 interest, and a longer time will be required to gain $360 interest, therefore the greater number (360) is placed on the right of the line. 130. In what time will $640 amount to $1018 at 7 per cent. a year? 1 Year. 640 100 #378-1018-640 32 $4 4270 14 | 21 Ans. 8 yrs. 5 mos. We divide 32 (and 12 times 14) by 8 and obtain 4 and 21. 131. In what time will $171.40 amount to $231.39 at 7 per cent. a year? In this solution we cancel 100, and then consider the 99 as whole numbers. i, 132. In what time will $189 amount to $252 at 8 per cent, Ans. 4 yrs. and 2 mos. (0.) a year? 133. In what time will $280 amount to $371 at 5 per cent. a year? Ans. 6 yrs. 6 mos. (0.) 134. In what time will $396 amount to $1144, at 8 per Ans. 22 yrs. 8 mos. (2.) cent. a year? 135. In what time will $4810.25 amount to $5002.66, at Ans. 8 months. (0.) 6 per cent. a year! 136. In what time will $684 amount to $931, at 6 per cent. a year? Ans. 5 yrs. 63 mos. (4.) 137. In what time will $675.25 amount to $864.32, at 4 per cent. a year? Ans. 7 years. (0.) 138. If I lend $275, at 3 per cent. a year, and on payment being made receive for principal and interest $342.37, what is the time? Ans. 7 years. (0.) 139. In what time will $540 amount to $734.40, at 4 per Ans. 9 years. (0.) cent. a year? 140. In what time will $37.43 amount to $74.86, at 6 per cent. a year? Ans. 163 years. (0.) In the last question observe the interest amounts to the same as the principal, that is, the principal is doubled, hence any sum will double itself, at 6 per cent. in 163 years. 141. In what time will $87.39 amount to $174.78, at 5 per cent.; or in what time will any sum double itself at 5 per cent.? Ans. 20 years. (0.) NOTE. To find the time required for any sum to double we simply divide 100 by the rate. 142. In what time will any sum double at 7 per cent. a year, at 8 per cent., 4 per cent., 9 per cent., 10 per cent., 11 per cent., 12 per cent. ? PARTIAL PAYMENTS. The United States Court has established a general rule for the computation of interest, when partial payments have been made, expressed by Chancellor Kent as follows: The rule for casting interest, when partial payments have been made, is to apply the payment in the first place to the discharge of the interest then due. If the payment exceeds the interest, the surplus goes towards discharging the principal, and the subsequent interest is to be computed on the balance of principal remaining due. If the payment be less than the interest, the surplus of interest must not be taken to augment the principal, but interest continues on the former principal until the period when the payments taken together exceed the interest due, and then the surplus is to be applied towards discharging the principal, and interest is to be computed on the balance as aforesaid. 1. $300. Philadelphia, May 1, 1842. For value received, I promise to pay James Thornton, or order, the sum of three hundred dollars on demand, with lawful interest. THOMAS CLARK. The following endorsements were made on this note: 1842, October 16, received $60.00. What was the balance due September 19, 1844? First find the time. 17.50. 28.40. 132.25. First payment, Amount of the note, Interest to October 16, 1842, (5 mos. 15 d.) First amount, Balance forming a new principal, Interest from October 16, 1842, to March 21, 1843, Interest from March 21, 1843, to August 27, 1843, Interest from August 27, 1843, to April 1, 1844, Balance due, brought forward, Interest from April 1, 1844, to September 19, 1844, (5 mos. 18 d.) $90.34 2.52 Ans. $92.86 Harrisburg, June 7, 1843. For value received, I promise to pay to James Taylor, or order, the sum of one thousand two hundred and sixty dollars, on demand, with lawful interest. HENRY DICKINSON. The following endorsements were made on this note: 1844, received August 19, 1846, received March 4, 1848, received September 13, What was the balance due July 3, 1849? $145.00 Interest from June 7, 1843, to August 19, 1844, $1260.00 (1 yr. 6 mos. 15 d.) Balance forming a new principal, Interest from August 19, 1814, to March 4, 1846, Second payment, less than the interest due, Leaving interest unpaid, 1205.72 111.53 36.40 75.13 |