Then you need to learn the definition of "permutation"! A permutation always involves different orders or arrangements. Combination" involve grouping different things without regard for order. Now, does this involve putting the books in different orders?sebastianbravom said:Homework Statement
in how many different ways can 7 different books be arranged in a row if
a. 3 specified books must be together,
b. two specified boks mus occupy both ends
Homework Equations
i don't udnerstand wether it is a permutation or a combination.
The Attempt at a Solution
a. 4! x 7!
b. 7 x 5! x 6
Permutation and combination are both ways of arranging a set of objects, but they differ in terms of order and repetition. Permutation involves arranging objects in a specific order, while combination does not take order into account. Additionally, permutation allows for repetition of objects, while combination does not.
In order to determine whether to use permutation or combination, you need to consider if the problem involves order and repetition. If the order of objects matters and repetition is allowed, then permutation should be used. If order does not matter and repetition is not allowed, then combination is the appropriate choice.
Yes, permutation and combination can be used in many real-life scenarios. For example, in a lottery, the order of numbers drawn is important, making it a permutation problem. In a committee of people, the order of their seating may not matter, making it a combination problem.
The formula for permutation is n! / (n-r)!, where n is the total number of objects and r is the number of objects being arranged. The formula for combination is n! / (r!(n-r)!), where n is the total number of objects and r is the number of objects being chosen.
One way to remember the difference is to think of a lock and a combination lock. In a lock, the order of numbers matters, making it a permutation problem. In a combination lock, the order of numbers does not matter, making it a combination problem.