Financial Maths Percentage Increase
First: work out the difference (increase) between the two numbers you are
comparing.
Percentages → A percentage is a number expressed as a fraction 𝑁𝑒𝑤 𝐴𝑚𝑜𝑢𝑛𝑡 − 𝑂𝑟𝑖𝑔𝑖𝑛𝑎𝑙 𝐴𝑚𝑜𝑢𝑛𝑡 100
over one hundred. 𝑃𝑒𝑟𝑐𝑒𝑛𝑡𝑎𝑔𝑒 𝐼𝑛𝑐𝑟𝑒𝑎𝑠𝑒 = 𝑥
𝑂𝑟𝑖𝑔𝑖𝑛𝑎𝑙 𝐴𝑚𝑜𝑢𝑛𝑡 1
Example: Zinhle buys an iPhone for R8000.00. The shop agrees to If your answer is a negative number, then this is a percentage decrease.
give her a discount of 10% for paying in cash. What amount will she
pay for the iPhone. Percentage Decrease
First: work out the difference (decrease) between the two numbers you
8000 10 are comparing.
𝑥 = 800 Decrease = Original Number - New Number
1 100
Zinhle will pay R8,000.00 – R800.00 = R7,200.00 Divide the decrease by the original number and multiply the answer by
100.
Cost Price → The price it cost to make a product without a profit % Decrease = Decrease ÷ Original Number × 100
If your answer is a negative number then this is a percentage increase.
or VAT being added.
Selling Price → The price of a product including profit and VAT
Interest → is the fee paid for the use of borrowed money or money
Finding Original Amount
earned by an investment. 100 𝑁𝑒𝑤 𝑃𝑟𝑖𝑐𝑒
Original Price = 100+𝑚𝑎𝑟𝑘−𝑢𝑝 𝑥 1
Profit and Loss
Example: Jake bought a cell phone for R5500 and sold it for R7000. Simple Interest
Calculate his percentage profit.
1500 𝑆𝑃−𝐶𝑃 100
• 𝑥 = 𝑝𝑥𝑟𝑥𝑛 𝑖
R7000 – R5500 = R1500 →
5500 𝐶𝑃 1 𝑆𝐼 = or 𝐴 = 𝑃 ( 1 + )𝑛
100 100
27,27%
Jake bought another cell phone, but this time he sold it at a 15% loss. P → Starting Amount
What price did he sell it for? A → Final Amount
15 𝑰𝒏𝒕𝒆𝒓𝒆𝒔𝒕
• 15% of R5500 = 100 𝑥 5500 = 825 → 5500 – 825 = R4675 I → Interest rate, written as
He sold it for R4675 𝟏𝟎𝟎
N → Number of years
First: work out the difference (increase) between the two numbers you are
comparing.
Percentages → A percentage is a number expressed as a fraction 𝑁𝑒𝑤 𝐴𝑚𝑜𝑢𝑛𝑡 − 𝑂𝑟𝑖𝑔𝑖𝑛𝑎𝑙 𝐴𝑚𝑜𝑢𝑛𝑡 100
over one hundred. 𝑃𝑒𝑟𝑐𝑒𝑛𝑡𝑎𝑔𝑒 𝐼𝑛𝑐𝑟𝑒𝑎𝑠𝑒 = 𝑥
𝑂𝑟𝑖𝑔𝑖𝑛𝑎𝑙 𝐴𝑚𝑜𝑢𝑛𝑡 1
Example: Zinhle buys an iPhone for R8000.00. The shop agrees to If your answer is a negative number, then this is a percentage decrease.
give her a discount of 10% for paying in cash. What amount will she
pay for the iPhone. Percentage Decrease
First: work out the difference (decrease) between the two numbers you
8000 10 are comparing.
𝑥 = 800 Decrease = Original Number - New Number
1 100
Zinhle will pay R8,000.00 – R800.00 = R7,200.00 Divide the decrease by the original number and multiply the answer by
100.
Cost Price → The price it cost to make a product without a profit % Decrease = Decrease ÷ Original Number × 100
If your answer is a negative number then this is a percentage increase.
or VAT being added.
Selling Price → The price of a product including profit and VAT
Interest → is the fee paid for the use of borrowed money or money
Finding Original Amount
earned by an investment. 100 𝑁𝑒𝑤 𝑃𝑟𝑖𝑐𝑒
Original Price = 100+𝑚𝑎𝑟𝑘−𝑢𝑝 𝑥 1
Profit and Loss
Example: Jake bought a cell phone for R5500 and sold it for R7000. Simple Interest
Calculate his percentage profit.
1500 𝑆𝑃−𝐶𝑃 100
• 𝑥 = 𝑝𝑥𝑟𝑥𝑛 𝑖
R7000 – R5500 = R1500 →
5500 𝐶𝑃 1 𝑆𝐼 = or 𝐴 = 𝑃 ( 1 + )𝑛
100 100
27,27%
Jake bought another cell phone, but this time he sold it at a 15% loss. P → Starting Amount
What price did he sell it for? A → Final Amount
15 𝑰𝒏𝒕𝒆𝒓𝒆𝒔𝒕
• 15% of R5500 = 100 𝑥 5500 = 825 → 5500 – 825 = R4675 I → Interest rate, written as
He sold it for R4675 𝟏𝟎𝟎
N → Number of years
