<em><u>Answer:
</u></em>
x + y + z = 28,000
0.035x + 0.0425y + 0.0475z = 1160
z = 0.75x
<em><u>Step-by-step explanation:
</u></em>
Let x = amount invested at 3.5%.
Let y = amount invested at 4.25%.
Let z = amount invested at 4.75%.
The total amount is $28,000.
<em><u>
Equation 1:
</u></em>
x + y + z = 28,000
The total interest is $1,160.
<em><u>Equation 2:
</u></em>
0.035x + 0.0425y + 0.0475z = 1160
"The amount of money in the 4.75% account was 75% of the
amount of money in the 3.5% account."
<em><u>Equation 3:
</u></em>
z = 0.75x
<em><u>
The system of equations is:
</u></em>
x + y + z = 28,000
0.035x + 0.0425y + 0.0475z = 1160
z = 0.75x
<em><u>Answers to the system of equations:</u></em>
The total amount in each account is:
x = $8,000
y = $14,000
z = $6,000