A man gets total 13.5% simple interest on a sum. If the ratio of numerical value of rate of interest to time period is 3 : 2, then find the interest received on a sum of Rs. 4000 after 4 years at the same rate of simple interest.

Rs. 720

Total Interest = rate(p.a.) x time = 3R x 2R = 6R² = 13.5

                                             ⇒ R = 1.5

⇒ Rate of interest p.a. = 3R = 3 x 1.5 = 4.5%

Now,

Simple Interest = \(\frac{4000 × 4.5 × 4}{100}\) = ₨. 720