A sum of money becomes \(\frac{39}{12}\) times of itself in 30 years at the rate of r% p.a. simple interest. Find the value of r.
Answer & explanation
Correct answer: option 3
Principal : Amount Simple Interest
12 : 39 ⇒ 27 (in 30 years)
Simple interest per year = \(\frac{27}{30}\) = \(\frac{9}{10}\)
Principal = 12
Rate of Interest (r) = \(\frac{9/10}{12}\) × 100% = 7.5 %