Topic Details (Notes format)

How to Calculate Permutations (Ordered Arrangements)

Subject: Mathematics

Book: Maths Mastery

Permutations count distinct ways to arrange a set of objects where order matters. The formula for the number of permutations of n distinct items taken k at a time is P(n, k) = n! / (n–k)!. For example, the number of ways to arrange 3 items out of 5 is P(5, 3) = 5! / 2! = 60. Permutations arise in tasks like planning seat arrangements, ordering steps in processes, or counting possible password permutations. This concept is key to combinatorial analysis, bridging real-life scenarios where item order is crucial—such as scheduling or competition ranks.

Practice Questions

If a = 5 and b = 12, what is the length of the hypotenuse of a right triangle?

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

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The LCM of two numbers is 60, and their HCF is 5. If one of the numbers is 20, what is the other number?

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If the radius of a circle is doubled, what happens to its area?

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The area of an equilateral triangle with side length 6 cm is:

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If the sum of three consecutive integers is 72, what are the integers?

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If x = 2 and y = 3, what is the value of (x^2 + y^2)?

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