Simple and Compound Interest

Simple interest formula is I = (P * R * T) / 100. Here, 50 = (5000 * R * 1) / 100. Solving for R gives R = 5000 / 5000 = 1%.

Simple Interest = 600 - 500 = 100. Principal = 500, Time = 4 years. Rate = (100*100)/(500*4) = 10000/2000 = 5%.

Simple interest: Amount = P(1 + RT/100). If it doubles in 30 years, 2P = P(1 + R*30/100), so 1 = 0.3R, R = 10/3 percent. To become 4 times, 4P = P(1 + (10/3)*T/100), so 3 = T/30, T = 90 years.

Simple interest = Amount - Principal = 540 - 450 = 90. Using SI = (P*R*T)/100, 90 = (450*5*T)/100. 90 = 22.5*T, so T = 90/22.5 = 4 years.

The compound interest for 4 years at 5% is 20000 * ((1.05)^4 - 1) = 20000 * (1.21550625 - 1) = 4310.125. The simple interest is 20000 * 0.05 * 4 = 4000. The difference is 310.125, which rounds to 310.

Using the compound interest formula A = P(1 + r/n)^(nt), where A=6000, P=4000, t=3, and n=2 (half-yearly), we get 6000 = 4000(1 + r/2)^6. Solving for r, (1.5)^(1/6) = 1 + r/2, which leads to r approximately 14%.

Present value = A / (1 + r/n)^(nt). Here, A = 500, r = 0.10, n = 2 (half-yearly), t = 10. PV = 500 / (1 + 0.05)^20 = 500 / (1.05)^20. 1.05^20 is approximately 2.653. 500 / 2.653 is approximately 188.44.

Simple interest formula: I = PRT/100. 28600 = 352000 * 0.025 * T. 28600 = 8800 * T. T = 28600 / 8800 = 3.25 years. 0.25 years is 3 months, so 3 years and 3 months.

Cash price is 600. Down payment is 300, remaining balance is 300. After 2 months, 360 is paid, so interest is 60. Simple interest formula: I = (P * R * T) / 100. 60 = (300 * R * (2/12)) / 100. 60 = 3 * R * (1/6) = R / 2. R = 120%.

Simple Interest = (P * R * T) / 100. 3840 = (P * 10 * 3) / 100, so P = 12800. The amount is Principal + Interest = 12800 + 3840 = 16640.

A = P(1 + r/100)^n. 88200 = 80000(1 + r/100)^2. 882/800 = (1 + r/100)^2. 441/400 = (1 + r/100)^2. (21/20)^2 = (1 + r/100)^2. 1 + r/100 = 1.05. r = 5%.