Simple interest on a certain amount is 9/16 of the principal. If the numbers representing the rate of interest in percent and time in years be equal, then time, for which the principal is lent out, is : Choices
A) 6 1/2	B) 7 1/2	C) 8	D) 9 1/2	E) None
Sol.   Let sum = x. Then, S.I. = 9/16 x.   Let rate = R% and time = R years.   ∴ [x * R * R / 100] = 9x / 16 ⇔ R² = 900/16   ⇔ R = 30/4 = 7 1/2   Hence, time = 7 1/2 years.   Answer 7 1/2
<result>B</result>
Simple interest on a certain amount is 9/16 of the principal. If the numbers representing the rate of interest in percent and time in years be equal, then time, for which the principal is lent out, is :