Using Percents in Tax, Tip, and Discount

Introduction

In this lesson, we will learn how we can use percents to calculate the tax, tip, and discount. Now this video will deal with money and so we will be using real-life examples to calculate the tax, tip and discount. So let's get started!

Percents in Tax

Ameyliah bought a new dress at Kohl's for $34.50. The tax on the dress was 5%. What was the total amount of money that Ameyliah had to pay for the dress?

The first step in calculating the tax is that you have to rewrite the percent, 5%, as a fraction.

We already know that a percent is part of 100, so 5% converted into a fraction should equal 5/100.

The next step is that we have to look at the price of the dress which is $34.50. This price will become our bottom number, or denominator, for our second fraction.

So now we have the following problem:

  5                ?

----  and   --------

100          $34.50

(The tax will become the numerator once we have finished the calculation)

In order to find the tax, we have to do cross multiplication. Since we don't have a numerator for our second fraction, we can't do 100.

So, we'll have to multiply 5 by $34.50 to get $172.5.  Now, we will divide this number by the remaining number, which is 100.

$172.5/100  equals $1.725 or $1.73

That means that the tax on Ameyliah's dress is $1.73!

5               $1.73

----  and   --------

100          $34.50

Now, the last step is that we have to add the price of the dress and the tax together to find the total cost that Ameyliah had to pay.

$34.50+$1.73  equals $36.23

The total amount of money that Ameyliah had to pay for the dress was $36.23.

Percents in Tip

Calculating the tip is the same thing as calculating the tax. You add the money for both.

Katheryne ate at a restaurant and had a bill of $26.78 including tax. She wanted to leave a 15% tip for the waitress. How much money did Katheryne leave as a tip?

The first step in calculating the tip is rewriting the percent as a fraction.

15% becomes 15/100

The next step is that we have to look at our bill, which is $26.78 and that will become our denominator for our second fraction. (The numerator will be the calculated tip.) 

15                    ?

----  equals ---------

100              $26.78

Now we have to do cross multiplication. Which two numbers can we multiply diagonally?  

15 and $26.78. 

15*26.78  equals $401.70

Now all we have to do is divide our answer by the remaining number which is 100:

$401.70/100  equals  $4.017  or $4.02.

That means the tip is $4.02!

Katheryne left $4.02 as a tip for the waitress.

Percents in Discount

When calculating the discount, the formula is the same as the formula for tax and tip but instead of adding the money to the original price, you need to subtract it!

Rozalynda went to the book store and bought 5 books for a total price of $53.67. She got a discount of 20% off of the total price. How much money did Rozalynda have to pay after the discount?

The first step is to rewrite the percent as a fraction:  20%  becomes 20/100.

Now look at your total price for all 5 books, which is $53.67 and write a fraction with this price as the denominator. (The numerator will be the calculated discount.) 

20                      ?

-----  equals  ---------

100                $53.67

Now do cross multiplication. Which two numbers can we multiply together diagonally? 20 and $53.67

20*53.67  equals  $1,073.40

Now we have to divide by the remaining number which is 100:

$1,073.4/100  equals $10.734 or $10.73

That means the calculated discount on the books is $10.73!

20                  $10.73

-----  equals  ---------

100                $53.67

The last step is to subtract the discount from the original price of the books:

$53.67 minus $10.73  equals $42.94.

Rozalynda had to pay $42.94 after her discount on the books.

Sheet 1 What is Tax, Tip, and Discount