Question 1128896
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By traditional algebra....<br>
8% of $4500, plus 5% of an unknown amount x, equals 6% of the total, $4500+x:<br>
{{{.08(4500)+.05(x) = .06(4500+x)}}}<br>
That equation is relatively easy to solve, although the decimals might make it take some time.<br>
Here is a MUCH easier way to solve the problem (assuming a formal algebraic solution is not required).<br>
(1) The overall average of 6% is "twice as close" to 5% as it is to 8%.
(2) Therefore, twice as much must be invested at 5% as at 8%.
(3) Since $4500 is invested at 8%, the amount required to be invested at 5% is 2*$4500 = $9000.<br>
ANSWER: $9000 at 5%<br>
CHECK:
.08(4500)+.05(9000) = 360+450 = 810
.06(13500) = 810