Question 1128550
{{{ A = P*e^(r*t) }}}
{{{ P = 18000 }}}
{{{ A = 36000 }}}
{{{ t = 41 - 30 }}}
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{{{ A = 18000*e^(r*11) }}}
{{{ 36000 = 18000*e^( 11r ) }}}
{{{ 2 = e^( 11r ) }}}
Take the ln of both sides
{{{ ln( 2 ) = 11r*1 }}}
{{{ r = ln( 2 ) / 11 }}}
{{{ r = .693147 / 11 }}}
{{{ r = .0630 }}}
She needs a rate of 6.3%