Question 111380
Let x=amount invested for 5%, y=amount for 3%


So we know the sum of the parts is the total $20,000. So this means 


{{{x+y=20000}}}



Also we know that 5% of x amount of dollars plus 3% of y amount of dollars is 4.5% of $20,000 (which is $900)


So 


{{{0.05x+0.03y=900}}}



{{{5x+3y=90000}}} Multiply both sides by 100 to make every number a whole number



*[invoke solving_linear_system_by_elimination 1, 1, 20000, 5, 3, 90000]

note: ignore the graph. It didn't turn out right


So $15,000 was invested at 5% and $5,000 was invested at 3%