6. college fund when melissa was born, her parents put $8,000 into a college fund account that earned 9%…

6. college fund when melissa was born, her parents put $8,000 into a college fund account that earned 9% simple interest. find the total amount in the account after 18 years.\n8. savings mona opened a savings account with a $500 deposit and a simple interest rate of 5.6%. if there were no deposits or withdrawals, how much money is in the account after 8\\frac{1}{2} years?

6. college fund when melissa was born, her parents put $8,000 into a college fund account that earned 9% simple interest. find the total amount in the account after 18 years.\n8. savings mona opened a savings account with a $500 deposit and a simple interest rate of 5.6%. if there were no deposits or withdrawals, how much money is in the account after 8\\frac{1}{2} years?

Answer

Explanation:

Step1: Recall simple - interest formula

The formula for simple interest is $I = Prt$, where $P$ is the principal amount, $r$ is the annual interest rate (in decimal form), and $t$ is the time in years. The total amount $A$ in the account after $t$ years is $A=P + I=P(1 + rt)$.

Step2: Solve for Melissa's college - fund problem

For Melissa, $P = 8000$, $r=0.09$ (since $9%=0.09$), and $t = 18$. Substitute these values into the formula $A=P(1 + rt)$: [ \begin{align*} A&=8000\times(1+0.09\times18)\ &=8000\times(1 + 1.62)\ &=8000\times2.62\ &=20960 \end{align*} ]

Step3: Solve for Mona's savings - account problem

For Mona, $P = 500$, $r = 0.056$ (since $5.6%=0.056$), and $t=8.5$. Substitute these values into the formula $A=P(1 + rt)$: [ \begin{align*} A&=500\times(1+0.056\times8.5)\ &=500\times(1+0.476)\ &=500\times1.476\ &=738 \end{align*} ]

Answer:

  1. The total amount in Melissa's college - fund account after 18 years is $$20960$.
  2. The total amount in Mona's savings account after $8\frac{1}{2}$ years is $$738$.