Question 1068716
Simple interest,
{{{I=Prt}}}
So the future value would be,
{{{F=P+I}}}
{{{F=P+Prt}}}
{{{F=P(1+rt)}}}
{{{2P=P(1+rt)}}}
{{{1+rt=2}}}
{{{rt=1}}}
{{{0.03t=1}}}
{{{t=1/0.03}}}
{{{t=33.3}}}{{{yrs}}}
.
.
.
If it's compounded interest,
{{{2P=P(1+i)^t}}}
{{{2=(1.03)^t}}}
{{{t=log((2))/log((1.03))}}}
{{{t=23.4}}}{{{yrs}}}
.
.
.
Neither equals 20.