At what rate of interest is an amount doubled in two years, when compounded annually?
Choose one.
A) 41.4%	B) 41.7%	C) 41.4%	D) 42.4%	E) 21.4%
Let the rate of interest be r. The amount gets doubled in two years   =&gt; P(1 + r/100)2 = 2p =&gt; 1 + r/100 = √2 =&gt; r/100 = √2 - 1   = 0.414 =&gt; r = 100(0.414)   = 41.4%   Answer:41.7%
<result>B</result>
At what rate of interest is an amount doubled in two years, when compounded annually?