I am in desperate need of assistance helping my son with his math homework on simple interest. Any guidance on these is appreciated!

1) If Marie makes an investment of $8,000that earns 2% interest annually, how much is the total investment worth after 3.5 years?

2) You invested $600 in a savings account that earns simple interest.After 20 years the account had earned $720 in interest.What was the interest rate on the account?Your answer can be in decimal or percent form.

3) You earn $45.50 each year on an investment.What is the rate of simple interest if your initial investment was $750?

Your answer can be in decimal or percent form.

4) Find the simple interest.$500.00 at 4% for 2 years

5) Find the simple interest. $200.00 at 5% for 3 years

6) Find the interest rate.You may answer in decimal form or percent form. Principal: $2,500, Time: 2 years; Interest: $450

7) Find the interest rate.You may answer in decimal form or percent form. Principal: $5,600, Time: 9 months, Interest $357

8) Find the length of time for the loan in years. Principal: $1,250, Rate: 6%, Interest: $300

9) Find the length of time for the loan in years. Principal: $4,800, Rate: 7.5%, Interest: $900

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