A sum lent out at simple interest becomes rs4480 in 3 years and rs 4800 in 5years. find the rate of interest

Answer: rate = 4%

Step-by-step explanation:

SI = 4800 - 4480 = 320 for two years

For 1 year, it is 320/2 = 160

For 5 years, it is 160 * 5 = 800

Principal = Amount - SI

P = 4800 - 800 = 4000

SI = prt / 100

800 = (4000 * r * 5) / 1000

r = 800 * 100 / 4000 * 5

r = 4%