If the compound interest for the 2nd and 3rd year on a certain principal is Rs. 100 and Rs. 130 respectively, what is the rate of interest (in %)?

30%

Compound interest for the 2nd year = 100

Compound interest for the 3rd year = 130

R% = \(\frac{ (CI \; for \; 3rd \; years) - (CI \; for \; 2nd \; year) }{(CI \; for \; 2nd \; year)}\)

R% = \(\frac{130 - 100}{100}\) × 100 = 30%