Question 804476
10% overall is {{{ .1*( 100000 + 150000 + 200000 ) }}}
{{{ .1*( 450000 ) = 45000 }}}
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{{{ .08*100000 = 8000 }}}
and
{{{ .12*150000 = 18000 }}}
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Let {{{ r }}} = the simple interest rate at
which $200,000 is invested
{{{ r*200000 }}} = the interest earned
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{{{ 8000 + 18000 + r*200000 = 45000 }}}
{{{ r*200000 = 45000 - 26000 }}}
{{{ r*200000 = 19000 }}}
{{{ r = .095 }}}
The $200,000 must be invested at 9.5% in
order to earn 10% overall
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check:
{{{ .095*200000 = 19000 }}}
{{{ 8000 + 18000 + 19000 = 45000 }}}
OK