A amount doubles itself in 15 years. what is the rate of interest?  Choose the correct option
A) 20/3 % B) 10/3 % C) 40/3 % D) 50/3 % E) 70/3 %
let amount be x &amp; rate of interest be r% annual then   (2x-x)=(x*15*r)/100   =&gt; 15r = 100   =&gt; r=20/3 %   20/3 %NSWER:20/3 %
<result>A</result>
A amount doubles itself in 15 years. what is the rate of interest?