Question
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find the permutation and combination of the
word “EXAMINATION” taking 4ata time.

Ask by Reed Ortega. in Nepal
Mar 25,2025

Upstudy AI Solution

Tutor-Verified Answer

Answer

There are 330 ways to choose 4 letters from “EXAMINATION” (combinations) and 7,920 ways to arrange those 4 letters (permutations).

Solution

To find the permutations and combinations of the word “EXAMINATION” taking 4 letters at a time, we first need to analyze the letters in the word.
The word “EXAMINATION” consists of 11 letters, with the following frequency of letters:
  • E: 1
  • X: 1
  • A: 1
  • M: 1
  • I: 2
  • N: 2
  • T: 1
  • O: 1

Step 1: Calculate Combinations

The number of combinations of selecting 4 letters from the 11 letters can be calculated using the formula for combinations:
Where:
  • is the total number of items (letters),
  • is the number of items to choose.

Step 2: Calculate Permutations

The number of permutations of selecting 4 letters from the 11 letters can be calculated using the formula for permutations:

Step 3: Calculate Both Values

Let’s calculate both the combinations and permutations for the word “EXAMINATION” taking 4 letters at a time.
  1. Combinations:
  2. Permutations:
Now, I will compute these values.
Solve the equation by following steps:
  • step0: Solve for :
  • step1: Reorder the terms:
  • step2: Divide both sides:
  • step3: Divide the numbers:

    Solve the equation .
    Solve the equation by following steps:
  • step0: Solve for :
  • step1: Reorder the terms:
  • step2: Divide both sides:
  • step3: Divide the numbers:

    The calculations for the combinations and permutations of the word “EXAMINATION” taking 4 letters at a time are as follows:
  1. Combinations:
  2. Permutations:
However, since combinations and permutations must be whole numbers, let’s compute the exact values for and again without the fractions.

Exact Calculations

  1. Combinations:
  2. Permutations:
Now, I will compute these values accurately.
Calculate the value by following steps:
  • step0: Calculate:
  • step1: Multiply the terms:
  • step2: Multiply the numbers:

    Calculate or simplify the expression .
    Calculate the value by following steps:
  • step0: Calculate:
  • step1: Multiply the terms:
  • step2: Multiply the terms:
  • step3: Reduce the fraction:

    The exact calculations for the combinations and permutations of the word “EXAMINATION” taking 4 letters at a time are:
  1. Combinations:
  2. Permutations:
Thus, the number of ways to choose 4 letters from “EXAMINATION” is 330 (combinations), and the number of ways to arrange those 4 letters is 7920 (permutations).

Answered by UpStudy AI and reviewed by a Professional Tutor

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The Deep Dive

To find the number of ways to arrange “EXAMINATION” taking 4 letters at a time, we first notice that the word has 11 letters with the letter ‘I’ appearing twice. For permutations, we have two scenarios: choosing 4 different letters or including the repeated letter.
  1. First, count the distinct letters in “EXAMINATION”: E, X, A, M, I (×2), N, T, O. That’s 8 distinct letters.
  2. If we choose 4 different letters from these 8, the number of arrangements (permutations) would be calculated as .
  3. If we choose the letter ‘I’ twice and two other distinct letters, the formula changes. Suppose we select 2 more letters from the 7 remaining distinct letters. The count for this scenario is arrangements of ‘I’, so it becomes .
In total, we get total arrangements.
Now, you’ve got a fun mix of math and letters, making “EXAMINATION” quite the lexical playground!

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