Multi-step problems with percents
Key notes:
β Understand What Is Given
- Read the problem carefully.
- Identify:
- The original value
- The percentage
- What is being asked (increase, decrease, discount, tax, profit, loss, etc.)
π Convert Percent to Decimal or Fraction
- Percent means βout of 100β
- Convert before calculating:
- 25% = 0.25
- 12.5% = 0.125
- 150% = 1.5
ββ Perform Steps in the Correct Order
Multi-step percent problems usually involve more than one operation:
- First: Find the percent of a number
- Next: Add or subtract (for increase or decrease)
- Sometimes: Repeat with a new percent
π Always solve step by step, not all at once.
πΈ Percent Increase Problems
Steps:
- Find the increase amount
β Increase = Original Γ Percent - Add to the original value
π Example idea:
Price increases by 10% β Add the increase to the original price.
π·οΈ Percent Decrease / Discount Problems
Steps:
- Find the discount amount
β Discount = Original Γ Percent - Subtract from the original value
π Used in:
- Discounts
- Sales
- Price reductions
π§Ύ Problems with Tax or GST
- First calculate the tax amount
- Then add it to the original price
π Tax is always calculated on the original price, not the total.
π Successive Percent Changes
- When more than one percent change is applied:
- Apply the first percent
- Use the new value for the next percent
- Do not add the percentages directly.
βοΈ Use Equations When Helpful
- Let the unknown be x
- Write equations like:
- Final value = Original Β± (Percent Γ Original)
This helps in word problems.
π Check Your Answer
- Does the answer make sense?
- Increase β final value should be greater
- Decrease β final value should be less
- Recheck calculations to avoid small mistakes.
π§ Common Mistakes to Avoid
β Adding percentages directly
β Forgetting to convert percent to decimal
β Skipping steps
β Using the wrong base value
β Tip for Students
π Write each step clearly
π Label values (βΉ, %, units)
π Practice with real-life examples like shopping and bills
Learn with an example
A store bought a tent at a cost of βΉ4,060 and marked it up 50%. Eliana, who works as a salesperson at the store, makes a 20% commission on all of her sales. Yesterday morning, Eliana sold the tent. How much commission did she make from this sale?βΉ———.
First find the price. Write 50% as the decimal 0.50 before using it in the equation.
price=cost+mark-up
=4060+0.50*4060
=4060+2030
=6090
The price was βΉ6,090.
Now find the commission. Write 20% as the decimal 0.20 before using it in the equation.
commission=commission percentageΓ sales
=0.20Γ6090
=1218
The commission was βΉ1,218.
A store purchased a bike light and marked it up 80% from the original cost of βΉ100. Then, wanting to make room for summer inventory, the store placed the light on sale for 5% off. What was the price after the discount?βΉ——–.
First find the original price. Write 80% as the decimal 0.80 before using it in the equation.
price=cost+mark-up
=100+0.80Γ100
=100+80
=180
The original price was βΉ180.
Now find the discount price. Write 5% as the decimal 0.05 before using it in the equation.
discount price=original price-discount
=180-0.50Γ180
=180-9
=171
The discount price was βΉ171.
A store priced a mobile phone at βΉ5,750 and later marked it down 60 percent. Today, a salesperson named Bobby sold the mobile phone, earning a 15% commission on the sale price. How much commission did Bobby make?βΉ—.
First find the discount price. Write 60% as the decimal 0.60 before using it in the equation.
discount price=original cost-discount
=5750-0.60Γ5750
=5750-3450
=2300
The discount price was βΉ2,300.
Now find the commission. Write 15% as the decimal 0.15 before using it in the equation.
commission=commission percentageΓ sales
=0.15Γ2300
=345
The commission was βΉ345.
let’s practice!

