Percent Reasoning REVIEW

7th Grade Math

UNIT 3

Percent Reasoning REVIEW

REMEMBER... there are two ways to find the percent of a number:

1) Set up a proportion:   $\frac{\%}{100}=\frac{Part\ \left("is"\right)}{Whole\ \left("of"\right)}$  

        25% of 500:    $\frac{25}{100}=\frac{n}{500}\ \ →\ \ \ n\ =\ \frac{\left(25\right)\left(500\right)}{100}\ \ =\ 125$ 

*****OR*****

2) Multiply the whole by the percent (written as a decimal)

       25% of 500  = 0.25  $\times$  500 = 125

% Increase: Markup, Including Tax or Tip:

Add the % increase to 100%, then multiply:

Ex) $300 with a 45% markup → 300(145%) = 300 (1.45) = 435                            $435 is the price after the markup

****Work it in reverse to find the original price***

Selling price is $512.  What was the price before a 25% increase?

 $\frac{512}{\left(1.25\right)}=409.6$     Original price: $409.60

Multiple Choice

Milk has increased in price by 6% in recent years. If today's price is approximately $3.60 how much was the ORIGINAL price of milk BEFORE the price increase?

• $0.22

• $0.21

• $3.40

• $3.54

Multiple Choice

Samuel wants to buy a skateboard that usually sells for $95.99 . The store is having a sale and all merchandise is DISCOUNTED by 16%.

What is the TOTAL COST of the scateboard if Samuel pays 6.5% sales tax?

• $90.48

• $80.63

• $85.87

• 106.45

Multiple Choice

A discount store purchased iphone chargers for $6.00 per charger. The store marked up the price of the charger by 35%.

What is the selling price of one charger?

• $2.10

• $41.00

• $6.35

• $8.10

Simple Interest:

Interest = Principal $\times$  Rate  $\times$  Time