Topic Details (Notes format)

How to Calculate the Percentage of a Number?

Subject: Mathematics

Book: Maths Mastery

Percentages are central to countless real-world applications—from calculating exam marks to determining discounts and interest rates. The general formula to find a percentage is: (Part / Whole) × 100%. However, if you already know the rate and the whole, use Percentage of a Number = (Rate ÷ 100) × Whole. For example, to calculate 20% of 150, convert 20% to 0.20, then multiply: 0.20 × 150 = 30. This concept is pivotal in areas like finance and data analysis, so practice by computing percentages for tips in restaurants, taxes on shopping bills, or proportionate contributions in group projects. Mastering this skill builds a strong foundation for advanced percentage operations such as percentage increase, decrease, and compound interest calculations.

Practice Questions

What is the area of a circle with a diameter of 14 cm?

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If x:y = 2:3 and z:y = 4:3, what is x:z?

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What is the square root of 121?

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If the average of five consecutive odd numbers is 25, what is the largest number?

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What is the remainder when 5^100 is divided by 3?

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A sphere has a radius of 7 cm. What is its volume?

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A train 150 m long passes a pole in 15 seconds. What is its speed?

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If a person can type 45 words per minute, how many words can they type in 2 hours?

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If x^3 - 3x^2 + 4 = 0, what is one root of the equation?

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