Compound & Reverse Percentages — Year 9 Practice Questions
Work through these Year 9 practice questions on compound and reverse percentages. Try each one before revealing the worked solution.
Questions
Write the multiplier for a 7% increase.
Write the multiplier for a 12% decrease.
Increase 250 by 8% using a multiplier.
$500 is invested at 4% compound interest per year. Find the value after 3 years.
A car worth $12 000 depreciates by 10% each year. Find its value after 2 years.
A coat costs $60 after a 20% increase. Find the original price.
In a sale, a price of $90 is 75% of the original. Find the original price.
A population of 8000 grows by 5% per year. Find the population after 2 years.
Answers & Worked Solutions
Question 1 Solution
Step 1: A 7% increase means 100% + 7% = 107%.
Step 2: As a multiplier that is 1.07.
Answer: 1.07
Question 2 Solution
Step 1: A 12% decrease means 100% − 12% = 88%.
Step 2: As a multiplier that is 0.88.
Answer: 0.88
Question 3 Solution
Step 1: Multiplier for +8% is 1.08.
Step 2: 250 × 1.08 = 270.
Answer: 270
Question 4 Solution
Step 1: Use 500 × 1.04³.
Step 2: 1.04³ = 1.124864, so 500 × 1.124864 = $562.43 (to the nearest cent).
Answer: $562.43
Question 5 Solution
Step 1: Multiplier for −10% is 0.9.
Step 2: 12 000 × 0.9² = 12 000 × 0.81 = $9720.
Answer: $9720
Question 6 Solution
Step 1: $60 represents 120%, so the multiplier is 1.2.
Step 2: 60 ÷ 1.2 = $50.
Answer: $50
Question 7 Solution
Step 1: $90 is 75%, so divide by 0.75.
Step 2: 90 ÷ 0.75 = $120.
Answer: $120
Question 8 Solution
Step 1: Multiplier for +5% is 1.05.
Step 2: 8000 × 1.05² = 8000 × 1.1025 = 8820.
Answer: 8820
Build strong foundations in Compound & Reverse Percentages
A free trial class with Teacher Rig helps your Year 9 child master Compound & Reverse Percentages now — so IGCSE Maths feels familiar, not frightening, later.
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