1. Day 8 Simple Interest.notebook February 20, 2013
OBJECTIVE: How do we find
simple interest?
Do Now
1.) How much would I pay on $160 worth of
goods if I also have to pay New York State
sale tax (8.625%)?
2.) I purchased a shirt for 37.50 and that
was after a discount of 25% off. What was
the original price of the shirt?
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2. Day 8 Simple Interest.notebook February 20, 2013
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3. Day 8 Simple Interest.notebook February 20, 2013
Anticipatory Set
Explain, in a complete sentence, your understanding of
interest when dealing with bank accounts.
Simple Interest Formula: I = prt
Where I = interest
p = principal
r = interest rate as a decimal
t = time in years
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4. Day 8 Simple Interest.notebook February 20, 2013
1
Find the simple interest if you
deposit $1,200 at an interest rate of
5.5% for 2 years.
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5. Day 8 Simple Interest.notebook February 20, 2013
2
Find the simple interest if you borrow
$1,000 at an interest rate of 9.75%
for 4 years.
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6. Day 8 Simple Interest.notebook February 20, 2013
3
Find the simple interest if you borrow
$2,500 at an interest rate of 8% for 15
years.
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7. Day 8 Simple Interest.notebook February 20, 2013
4
Find the simple interest if you deposit
$1250 at an interest rate of 3.5% for 6
months. (HINT: Look back at the
formula written in your notes)
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8. Day 8 Simple Interest.notebook February 20, 2013
5
Find the simple interest if you borrow
$7500 at an interest rate of 5.5% for 9
months. (HINT: Look back at the
formula written in your notes)
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9. Day 8 Simple Interest.notebook February 20, 2013
6
4 years ago I deposited $500 into a savings
account, but I forgot the interest rate. If
the simple interest was $140, what is the
interest rate?
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10. Day 8 Simple Interest.notebook February 20, 2013
7
I deposited $15000 into a savings account
that has a interest rate of 5%. I want to
know how long it will take to reach $2250 in
simple interest. How long will it take?
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11. Day 8 Simple Interest.notebook February 20, 2013
Before You Leave
Compound Interest
Mortgage Payments
P[i(1 + i)]n
M=
[(1 + i)n - 1]
P = Principal
i = rate divided by 12
n = number of months
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12. Day 8 Simple Interest.notebook February 20, 2013
Mr. Tjersland's Math 7
Homework: None
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