The simple interest on a certain amount of money is 45% of the principal amount. The time for which the money was lent is four-fifth of the numerical value of the rate percent per annum. What is the rate percent per annum?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 7.5%.
Let the rate percent per annum be R.
Given, SI = 45% of P
Also, T = (4/5)R
SI = PRT/100
⇒ (45/100)P = P × R/100 × (4/5)R
⇒ 45 = 4R2/5
⇒ R2 = 225/4
⇒ R = 15/2 = 7.5%