Rs.2401 becomes Rs.4096 in four years at compound interest. The rate of interest per annum is:

14\(\frac{2}{3}\)% 15\(\frac{2}{3}\)% 14% 15%

14\(\frac{2}{3}\)%

In 3 years : Principal : Amount = 2401 : 4096= (7)4 : (8)4 In 1 year : Principal : Amount = \(\sqrt[4]{7^4 }\) : \(\sqrt[4]{8^4 }\) = 7 : 8 Interest = 8 - 7 = 1R Interest rate = \(\frac{1}{7}\) × 100% = 14\(\frac{2}{3}\)%