Correct Answer - Option 2 : 10%
GIVEN:
Principal = Rs.3000
Amount after 3 years = Rs.3993
CONCEPT:
As, interest is compounded annually for 3 years, we have to cube root both principal and amount and compare them to find the interest.
FORMULA USED:
Amount = Principal (1 + Rate/100)t
CALCULATION:
Ratio of principal and amount = 3993/3000 = 1331/1000
Cube root of ratio = ∛(1331/1000) = 1.1
After 1-year amount is 1.1 times that of principal
Percentage change = (1.1 -1) × 100 = 10%.
∴ Rate of Interest is 10% per annum.
