Rani took a loan of Rs. 1600 with simple interest for as many years as the rate of interest. If she paid Rs. 256 as interest at the end of the loan period, what was the rate of interest? Choose the correct choice from the following answers.
A) 3 B) 4 C) 5 D) 6 E) 7
Let rate = R% and time = R years.   Then, (1600 * R * R) / 100 = 256   16R2 = 256   R2 = 16 =&gt; R = 4   Answer:4
<result>B</result>
Rani took a loan of Rs. 1600 with simple interest for as many years as the rate of interest. If she paid Rs. 256 as interest at the end of the loan period, what was the rate of interest?