Question 1093436
Use {{{ I = P*r*t }}}
Let {{{ P[1] }}} = amount invested @ 5%
{{{ P[2] = 2*P[1] + 221 }}} = amount invested @ 7%
{{{ t = 1 }}} = 1 year
Let {{{ I[1] }}} = interest made @ 5% for 1 yr
{{{ I[2] = 850.52 - I[1] }}} = interest made at 7% for 1 yr
-----------------------------------------------
{{{ I[1] = P[1]*r[1]*t }}}
{{{ I[1] = P[1]*.05*1 }}}
(1) {{{ I[1] = .05P[1] }}}
-------------------------
{{{ 850 - I[1] = ( 2P[1] + 221 )*.07*1 }}}
{{{ 850.52 - I[1] = .14P[1] + 15.47 }}}
(2) {{{ I[1] = -.14P[1] + 835.05 }}}
------------------------------------
Set (1) = (2)
{{{ .05P[1] = -.14P[1] + 835.05 }}}
{{{ .19P[1] = 835.05 }}}
{{{ P[1] = 4395 }}}
and
{{{ P[2] = 2P[1] + 221 }}}
{{{ P[2] = 2*4395 + 221 }}}
{{{ P[2] = 8790 + 221 }}}
{{{ P[2] = 9011 }}}
---------------------------------------
$4,395 invested @ 5%
$9,011 invested @ 7%
-------------------------
check:
{{{ I[1] = 4395*.05 }}}
{{{ I[1] = 219.75 }}}
and
{{{ I[2] = 9011*.07 }}}
{{{ I[2] = 630.77 }}}
--------------------------
{{{ I[1] + I[2] = 219.75 + 630.77 }}}
{{{ I[1] + I[2] = 850.52 }}}
OK