Simple and Compound Interest

Amount = P + SI = P + (P*R*T)/100. 11360 = P + (P*16*3)/100 = P(1 + 0.48) = 1.48P. P = 11360 / 1.48 = 7675.67.

Simple interest for 2 years is 100, so SI for 1 year is 50. Compound interest for 2 years is 104, meaning the extra 4 is the interest on the first year's interest (50). Rate = (4/50) * 100 = 8%.

Interest for 3 years (7-4) = 1525 - 1300 = 225. Interest for 1 year = 75. Interest for 4 years = 300. Principal = 1300 - 300 = 1000. Rate = (Interest * 100) / (P * T) = (75 * 100) / (1000 * 1) = 7.5%.

Interest for 3 years (5-2) = 1350 - 1260 = 90. Interest for 1 year = 30. Principal = 1260 - 2*30 = 1200. Rate = (30/1200) * 100 = 2.5%.

Simple interest for 2 years (5-3) is 750 - 690 = 60. Interest for 1 year is 30. Interest for 3 years is 90. Principal = Amount - Interest = 690 - 90 = 600.

Simple interest: Amount = P(1 + RT/100). If it doubles, 2P = P(1 + R*8/100), so 1 = 8R/100, R = 100/8 = 12.5 percent.

Simple interest is PRT/100. Thus, 50 = 500 x 5 x T/100 = 25T, giving T = 2 years.

Amount = P + SI = P + (P * R * T) / 100. 8100 = P + (P * 7 * 5) / 100 = P + 0.35P = 1.35P. P = 8100 / 1.35 = 6000.

Simple interest doubles the principal in 10 years, meaning the interest earned equals the principal in 10 years. To triple the amount, the interest earned must be twice the principal, which takes 20 years.

Simple interest formula: SI = P * R * T / 100. Amount = P + SI = 5P, so SI = 4P. 4P = P * R * 20 / 100. 4 = R / 5. R = 20%.

This is an annuity due. Future Value = P * [((1+r)^n - 1) / r] * (1+r) = 10000 * [((1.09)^10 - 1) / 0.09] * 1.09 = 10000 * [1.36736 / 0.09] * 1.09 = 10000 * 15.1929 * 1.09 = 165603.

Total interest = (600 * r * 2 / 100) + (150 * r * 4 / 100) = 90. 12r + 6r = 90. 18r = 90, so r = 5%.

Simple interest: A = P + SI. Triples in 5 years means SI = 2P in 5 years. So, SI = P per 2.5 years. To become 5 times, SI = 4P. Time = 4P / (P / 2.5 years) = 10 years.

Simple interest I = P * R * T. Here I = 117, R = 0.09 per year, T = 5/12 years. 117 = P * 0.09 * (5/12). 117 = P * (0.45 / 12) = P * 0.0375. P = 117 / 0.0375 = 3120.