1. Using Percents to Solve Problems
Math 7/8

2. Discounts
Find discount by multiplying percent (decimal value) by the price.
Subtract the discount amount from the original price.
EX) 30% discount on $450 desk
.30 (450) = 135
450 – 135 = 315
The sale price is $315

3. Sales Tax
Find amount of tax by multiplying the percent tax rate (decimal value) by the original price of the item.
Add the tax amount to the original price to get the total.
EX) $39 dress and sales tax is 6%
.06 (39) = 2.34 =
The cost of the dress including tax is $41.34

4. Tips Find tip by multiplying percent (decimal value) by the total.
Add the tip amount to the final total bill.
Often times the tip is rounded to the nearest dollar
EX) 15% tip on a bill of $26.93
.15 (26.93) = 4.04
= 30.97
***round up to $31 total including tip

5. Simple Interest Review
The formula for interest is:
I = prt
I = interest
p = principle (amount of savings or loan)
r = rate (decimal form)
t = time in years
EX) Sarah borrowed money from the bank to buy a car. The car was $7,800. She has to pay 4.5% interest for 36 months. How much will Sarah end up paying for her car?