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permutation or combination? directions: recall that a permutation is an…

Question

permutation or combination?
directions: recall that a permutation is an arrangement with a specific order, while a combination is a group with no specific order. determine whether the example represents a permutation or combination, then solve.

examplep or c?work solution and answer
2) how many ways can 13 students line up for lunch?
3) how many ways can you make a 3 - letter arrangements out of the letters in the word trapezoid.
4) how many ways can you choose 2 books from a shelf of 40 books?
5) how many ways can 12 swimmers finish in first, second, and third place?
6) how many ways can mrs. sullivan choose two students from 27 to help put away calculators at the end of class?
7) how many different 12 - letter arrangements can be made using the letters in the word indianapolis?
8) how many different 11 - letter arrangements can be made using the letters in the word firecracker?
9) there are 18 offensive players on the hockey team. how many ways can the coach choose a left wing, center, and right wing to start the game?

Explanation:

Response
Problem 1:

Step1: Identify P or C

Choosing candy bars, order doesn't matter, so combination (C).

Step2: Apply combination formula

The formula for combinations is \( _nC_r=\frac{n!}{r!(n - r)!} \), where \( n = 30 \), \( r=4 \).
\( _{30}C_4=\frac{30!}{4!(30 - 4)!}=\frac{30!}{4!×26!}=\frac{30×29×28×27}{4×3×2×1} \)

Step3: Calculate the value

\( \frac{30×29×28×27}{24}=\frac{30×29×28×27}{24}=27405 \)

Step1: Identify P or C

Lining up students, order matters, so permutation (P).

Step2: Apply permutation formula

The formula for permutations is \( _nP_r=\frac{n!}{(n - r)!} \), where \( n = 13 \), \( r = 13 \) (since we are lining up all 13 students).
\( _{13}P_{13}=\frac{13!}{(13 - 13)!}=\frac{13!}{0!}=13! \)

Step3: Calculate the value

\( 13!=13×12×11×\cdots×1 = 6227020800 \)

Step1: Identify P or C

Making letter arrangements, order matters, so permutation (P). First, find the number of distinct letters in "TRAPEZOID". The word "TRAPEZOID" has 9 distinct letters (T, R, A, P, E, Z, O, I, D). We are making 3 - letter arrangements, so \( n = 9 \), \( r=3 \).

Step2: Apply permutation formula

Using \( _nP_r=\frac{n!}{(n - r)!} \), with \( n = 9 \), \( r = 3 \).
\( _{9}P_{3}=\frac{9!}{(9 - 3)!}=\frac{9!}{6!}=9×8×7 \)

Step3: Calculate the value

\( 9×8×7 = 504 \)

Answer:

P or C? : C; Number of ways: \( 27405 \)

Problem 2: