1. PERCENTAGE INCREASE/DECREASE
Finding the New Value
Given: Original Value & Percentage
Finding the Percentage
Given: Original Value & New Value
Finding the Original Value
Given: New Value & Percentage

2. A gaming shop pays the wholesaler €40 for a Fifa17 game, then sells it at €75. What is the mark-up rate?
Think
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87.5 %

3. An item that regularly sells for €425 is marked down to €340
An item that regularly sells for €425 is marked down to €340. What is the discount rate?
Think
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Share
20 %

4. Consider two methods: Method 1: Use the formula
(New Value = Original Value x multiplier)
Method 2: Use the percentage change formula

5. Method 1 New Value = Original Value x multiplier
New Value ÷ Original Value = multiplier
Write multiplier as a percentage (x 100)
Subtract 100

6. New Value = Original Value x multiplier
A gaming shop pays the wholesaler €40 for a Fifa17 game, then sells it at €75. What is the mark-up rate?
New Value = Original Value x multiplier
New Value ÷ Original Value = multiplier
75 ÷ 40 = 1.875
1.875 x 100 = 187.5%
187.5% - 100% = 87.5%

7. Method 2 First find the DIFFERENCE: New Value – Original Value (INC)
Original Value – New Value (DEC)
Then find this change as a PERCENTAGE:
𝑫𝑰𝑭𝑭𝑬𝑹𝑬𝑵𝑪𝑬 𝑶𝒓𝒊𝒈𝒊𝒏𝒂𝒍 𝑽𝒂𝒍𝒖𝒆 ×𝟏𝟎𝟎
You are finding the difference as a percentage of the original value

8. 35 40 ×100=87.5% New Value - Original Value = 75 – 40 = 35
A gaming shop pays the wholesaler €40 for a Fifa17 game, then sells it at €75. What is the mark-up rate?
New Value - Original Value = 75 – 40 = 35
This change is always relative to the original value and must be expressed as a percentage
35 40 ×100=87.5%

9. Method 1 New Value = Original Value x multiplier
New Value ÷ Original Value = multiplier
Write multiplier as a percentage (x 100)
Subtract 100

10. New Value = Original Value x multiplier
An item that regularly sells for €425 is marked down to €340. What is the discount rate?
New Value = Original Value x multiplier
New Value ÷ Original Value = multiplier
340 ÷ 425 = 0.8
0.8 x 100 = 80%
100% - 80% = 20%

11. Method 2 First find the DIFFERENCE: New Value – Original Value (INC)
Original Value – New Value (DEC)
Then find this change as a PERCENTAGE:
𝑫𝑰𝑭𝑭𝑬𝑹𝑬𝑵𝑪𝑬 𝑶𝒓𝒊𝒈𝒊𝒏𝒂𝒍 𝑽𝒂𝒍𝒖𝒆 ×𝟏𝟎𝟎
You are finding the difference as a percentage of the original value

12. 85 425 ×100=20% New Value - Original Value = 425 – 340 = 85
An item that regularly sells for €425 is marked down to €340. What is the discount rate?
New Value - Original Value = 425 – 340 = 85
This change is always relative to the original value and must be expressed as a percentage
×100=20%

13. Always CHECK that your answer makes sense !!!

14. Example: Percentage Increase
A house increases in value from €80,000 to €100,000. Calculate the percentage increase Find difference : €100,000 – €80,000 = €20,000 𝟐𝟎𝟎𝟎𝟎 𝟖𝟎𝟎𝟎𝟎 ×𝟏𝟎𝟎= 𝟏𝟎𝟎÷𝟒=𝟐𝟓% 1 4

15. Example: Percentage Decrease
Cara bought a car for €12,000. One year later she sold it for €8,400. Work out her percentage loss Find difference : €12,000 – €8,400 = €3,600 𝟑𝟔𝟎𝟎 𝟏𝟐𝟎𝟎𝟎 ×𝟏𝟎𝟎 =𝟑𝟎% 3 1

16. Hw Q1 A shop buys Justin Bieber figures in boxes of 50 units.
The shop purchases 10 boxes of dolls.
The total cost of purchasing the 10 boxes was €6000.
Each doll was sold at a price of €15
Q: Find the following:
Cost Price of each doll
The profit made on each doll.
The profit percentage made on each doll.

17. HW Q2
Newcastle Football Player Demba Ba wears Adidas F50 adiZero Football Boots.
The selling price of these football boots is €180.
This cost price of these football boots is €150
Questions:
Find the percentage profit made on these football boots.
Find the percentage profit made if the boots were sold at €165.