The simple interest on a sum of money is \(\frac{18}{25}\) of the sum. If the number of years is numerically half the rate per annum, then find the rate percent per annum.
Answer & explanation
Correct answer: option 1
SI = \(\frac{18 → SI}{25→ principal}\)
Let rate = 2x%, then year = x
SI = \(\frac{P × R × T}{100}\)
18 = \(\frac{25 × 2x × x}{100}\) ⇒ x2 = 36
x = 6 then rate = 2x = 12%