Question 1122575
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Let the amount invested be x.<br>
The total interest earned, $6300, is
(1) 4% of the 20% of x: (.04)(.20)(x); plus
(2) 7% of the 50% of x: (.07)(.50)(x); plus
(3) 9% of the 30% of x: (.09)(.30)(x)<br>
{{{(.04)(.20)(x)+(.07)(.50)(x)+(.09)(.30)(x) = 6300}}}<br>
The equation is easily solved to find the answer.