11.4 Practical Examples

Here are some real-life example uses of percentages. This time, it's more about the transaction that happens among us in our daily life.

• If you buy something and sell it, the differences between the two prices is a profit or a loss.

          It is given as a percentage of the buying price.
          If you buy something for $20 and sell it for $15 you make a loss of $5 or 25%

• When you buy something you may be offered a discount.

          This is a reduction in the price. It is usually given as a percentage.
          If the price is normally $20 and you get a 10% discount, you only pay 18%.

• If a bank helps you to buy an item, you may have to pay back more than you borrow. This is the interest that the bank charges. 

          It is given as a percentage of the cost.
          If a car costs $20 000 and the rate of the interest is 3$, you will pay $20 600.

• If you buy something the price may include a tax. This is called a purchase tax. When you earn money you may have to pay tax on what you earn. This is called income tax.

Let's take a look and see if we can solve the question below!

Worked Example:
A man earns $45 000 in a year.
He can earn $16 000 without paying any tax. He pays 24% tax on anything above $16 000.

a. Work out how much tax he pays.
answer:
$45 000 - $16 000 = 29 000    [This is his taxable income. He pays tax on this amount.
24% of 29 000 = 6 960            [That is 0.24 x 29 000]
He pays $6 960

b. What percentage of his income does he pay in income tax?
answer:
6960 / 45 000 x 100
= 15.5%                                     [45 000 = 100%. This answer is rounded to one decimal place]


Another questions? That'll do!

Question 1:
A restaurant must add 15% tax to the price of a meal.

a. Here are some bill totals before tax is added. Work out the bill after tax is added.
    i. $42.20 ii. $19.50
 answer:
i. $42.20 + (15 / 100 x 42.20)
   = $48. 53
ii. $19.50 + (15 / 100 x 19.50)
   = $22.43

Question 2:

A man invests $4500 in a bank. The bank pays 8% interest.
a. Work out the interest, in dollars.
answer: 
8 / 100 x $4500
= $360
b. Work out the total.
answer:
$4500 + $360
= $4860
Got it? If you still don't get this subchapter please kindly contact the math teacher.

As this is the end of the chapter, I hope Allah eases you in learning this chapter and I hope the posts I made about these are helpful to you.

The video below also explain about this subchapter!! :D