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Laabri

121 Solve for rate or time

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Last updated over 5 years ago
15 Nsɛmmisa

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Notes L7-2b: Solving for Rate or Time

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You can do the next 2 sections of DeltaMath.

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1.

Aaron invested $7,000 in an account paying an interest rate of 3\tfrac{5}{8}​% compounded continuously. Mia invested $7,000 in an account paying an interest rate of 3\tfrac{3}{4}​% compounded monthly. After 17 years, how much more money would Mia have in her account than Aaron, to the nearest dollar?

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2.

Dominic is going to invest $1,800 and leave it in an account for 17 years. Assuming the interest is compounded annually, what interest rate, to the nearest tenth of a percent, would be required in order for Dominic to end up with $4,700?

What is the equation?

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3.

Solve for r.

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4.

Amelia is going to invest $90,000 and leave it in an account for 12 years. Assuming the interest is compounded monthly, what interest rate, to the nearest hundredth of a percent, would be required in order for Amelia to end up with $144,000?

What is the equation?

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5.

What is the rate?

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6.

Avery is going to invest $270 and leave it in an account for 20 years. Assuming the interest is compounded continuously, what interest rate, to the nearest hundredth of a percent, would be required in order for Avery to end up with $600?

What is the equation?

Asemmisa {{asɛmmisaAhyɛnsode}}
7.

To solve, you will need to get rid of e.

rhetorical Q: What function (button) will do so?

Solve for the rate.

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8.

Tyler invested $350 in an account paying an interest rate of 4.5% compounded continuously. Assuming no deposits or withdrawals are made, how long would it take, to the nearest tenth of a year, for the value of the account to reach $700?

What is the equation?

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9.

How long will it take?

In the previous 2 examples, we used the ln function to elimnate e.

y=ln{x} is called the natural logarithm and is the inverse of the exponential funcion y=e^x.

We will use it solve for time (when the base isn't e). Then, we just have to ln both sides of the equation.

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10.

Example: Madeline invested $2,800 in an account paying an interest rate of 4.4% compounded annually. Assuming no deposits or withdrawals are made, how long would it take, to the nearest tenth of a year, for the value of the account to reach $6,100?

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11.

Aubree invested $4,400 in an account paying an interest rate of 2.4% compounded quarterly. Assuming no deposits or withdrawals are made, how long would it take, to the nearest tenth of a year, for the value of the account to reach $6,880?

What is the equation?

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12.

How long will it take?

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13.

Ella invested $4,900 in an account paying an interest rate of 3% compounded monthly. Assuming no deposits or withdrawals are made, how long would it take, to the nearest tenth of a year, for the value of the account to reach $5,920?

What is the equation?

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14.

How long will it take?

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15.

Choose all that are true