A sum of money at simple interest becomes 3 times of itself in 8 years. In how much time it will become 8 times of itself? Find the Interest rate also.

25 years; 28% 20 years; 30% 28 years; 25% 30 years; 20%

28 years; 25%

P : A = 1 : 3 S.I. = 2 rate = \(\frac{2}{8}\) x 100 = 25% P : A = 1 : 8 S.I. = 7 time =  \(\frac{7}{25}\) x 100 = 28 years