Resources

Resources

Compound interest: word problems

f(x) = \begin{cases} -x

-4

3

2

-7

3

10

120

5

10

4

\newline

9

\newline

-1

\newline

7

\newline

16

\$6,000

in a savings account, and after

7

years, the balance grew to

\$9,123.45

. The interest is compounded annually. What is the annual interest rate? Use the formula

A = P(1 + \frac{r}{n})^{nt}

A

is the balance (final amount),

P

is the principal (starting amount),

r

is the interest rate expressed as a decimal,

n

is the number of times per year that the interest is compounded, and

t

is the time in years. Round your answer to the nearest tenth.

\$4,000

in a savings account, and after

9

years, the balance grew to

\$6,561.60

. The interest is compounded annually. What is the annual interest rate? Use the formula

A = P\left(1 + \frac{r}{n}\right)^{nt}

A

is the balance (final amount),

P

is the principal (starting amount),

r

is the interest rate expressed as a decimal,

n

is the number of times per year that the interest is compounded, and

t

is the time in years. Round your answer to the nearest tenth.

\$7,500

in a savings account, and after

8

years, the balance grew to

\$12,282.50

. The interest is compounded annually. What is the annual interest rate? Use the formula

A = P\left(1 + \frac{r}{n}\right)^{nt}

A

is the balance (final amount),

P

is the principal (starting amount),

r

is the interest rate expressed as a decimal,

n

is the number of times per year that the interest is compounded, and

t

is the time in years. Round your answer to the nearest tenth.

\$2,500

in a savings account, and after

6

years, the balance grew to

\$3,397.50

. The interest is compounded annually. What is the annual interest rate? Use the formula

A = P\left(1 + \frac{r}{n}\right)^{nt}

A

is the balance (final amount),

P

is the principal (starting amount),

r

is the interest rate expressed as a decimal,

n

is the number of times per year that the interest is compounded, and

t

is the time in years. Round your answer to the nearest tenth.

\$3,000

in a savings account, and after

5

years, the balance grew to

\$4,665

. The interest is compounded annually. What is the annual interest rate

?

\newline

Use the formula

A = P\left(1 + \frac{r}{n}\right)^{nt}

A

is the balance (final amount),

P

is the principal (starting amount),

r

is the interest rate expressed as a decimal,

n

is the number of times per year that the interest is compounded, and

t

is the time in years.

\newline

Round your answer to the nearest tenth.