1. Consumer Applications Review

2. Finding the percent of a number
What percent of 780 is 3.9?
Set up an equation
Remember:
What becomes your variable
Is becomes =
Of becomes multiply
Y · 780 = Solve by using inverse operations
Y = 3.9 ÷ Y = = .5%

3. To find the sales tax on an item
Multiply the price by the sales tax percent
A computer sells for $700. The sales tax is 5%. What is the tax, and the final cost?
$700 x 5% = $35.00 (tax)
$700 + $35.00 = $ (final cost)

4. To find the unit rate Unit rate means how much would one cost
Divide the total cost by the number of items
Example 8 apples cost $2.40
$2.40 ÷ 8 = $0.30 for one apple

5. To find discount
Remember: Calculating the price with a discount is the only time you subtract!!!
Multiply the total by the discount percent
Then subtract the discount from the original price to get the final price
Example: A DVD costs $25.00 it is on sale with a 25% discount. What is the discount and sale price
$25.00 x 25% = $6.25 (discount)
$25.00 – $6.25 = $18.75 (sale price)

6. To find interest Principal x Rate x Time
Interest is always in annual terms, so watch for questions that ask for months.
Example: You borrow money for a car. $15,000 at 7% for 3 years
$15,000 x 7% x 3 = $3150 (interest)
$15,000 + $3150 = $18,150 (Final cost)

7. To solve a proportion Use cross-multiplication and set up an equation
x =
3x = 6 Solve for x by doing inverse operation
x = 2

8. To decide if 2 ratios are proportional
Use cross-multiplication
If the products are equal then the ratios are equal (proportional)
2 =
2 x 3 = 6 and 6 x 1 = 6
So they are proportional