Simple Interest (notes)

Simple Interest

Simple Interest - earnings paid on a FIXED amount of money or principal.

​FORMULA:

​I = Prt

(I = P × r × t)

​I-Interest (earned)

​P-Principal (starting amount of money)

​t- Time (in years)

​r- Rate %(as a decimal)

Ex.1) ​Find the simple interest and the total amount in the account:

• P = $1,800

• r = 5%

• t = 1 year

​

​I = Prt

Fill in the Blank

Ex. 2) Find the total amount in the account (DO NOT put a $ in front):

P = $2,600

r = 12%

t = 3 years

​I = Prt

Fill in the Blank

Ex. 3) Find the total amount in the account (DO NOT put a $ in front):

P = $5,660

r = 11%

t = 6 months

​I = Prt

​Ex. 4) Ben deposited $6,500 in a simple interest account that pays 2.8% interest annually. If Ben leaves the money in the account for 12 years, how much interest will he earn?

• P =

• r =

• t =

​

​I = Prt

​Ex. 5) Gonzalo has $1360 in a savings account that earns 2.5% interest per year. The interest is not compounded. How much interest will he earn in 10 years?

• P =

• r =

• t =

​

​I = Prt

Fill in the Blank

Ex. 6) Krysta has $70 in a savings account that earns 10% per year. The interest is not compounded. How much will she have in 3 years? (DO NOT put a $ in front)

P =

r =

t =

Fill in the Blank

Ex. 7) Jessica has $1500 in a savings account that earns 4% annually. The interest is not compounded. How much will she have in 5 years? (DO NOT put a $ in front)

P =

r =

t =

​I = Prt

Fill in the Blank

Ex. 8) Derek deposited $3,000 in a simple interest account 3 years ago. He has earned $360 in interest so far. What is the interest rate for his account? (make sure to put a %)

P =

r =

t =

​I = Prt