Question:medium

In how many ways can the letters of the word MATHEMATICS be arranged so that all the vowels always come together?

Show Hint

When certain letters must be together, treat them as a single unit. Then arrange the units and the internal arrangement separately.
Updated On: Jun 15, 2026
  • 11
  • 4989600
  • 20660
  • 120960
  • 120880
Show Solution

The Correct Option is D

Solution and Explanation

Step 1: Understanding the Concept:
When specific items must be "together", we treat them as a single block or entity. We then arrange this block along with the remaining letters, accounting for repetitions using the multinomial permutation formula.
Step 2: Key Formula or Approach:
Total arrangements = (Arrangements of entities including the block) \(\times\) (Internal arrangements of the block). Formula: \( \frac{n!}{p!q!...} \) for repeated items.
Step 3: Detailed Explanation:
In the word "MATHEMATICS": Consonants: M, T, H, M, T, C, S (7 letters: M repeats twice, T repeats twice). Vowels: A, E, A, I (4 letters: A repeats twice). 1. Treat the 4 vowels [AAEI] as one single block. 2. Total entities to arrange = 7 consonants + 1 vowel block = 8 entities. Arrangements of 8 entities = \( \frac{8!}{2! \times 2!} \) (dividing by \(2!\) for M and \(2!\) for T). \[ \frac{40320}{4} = 10080 \] 3. Internal arrangements of the vowel block [AAEI] = \( \frac{4!}{2!} \) (dividing by \(2!\) for A). \[ \frac{24}{2} = 12 \] 4. Total permutations = \( 10080 \times 12 = 120960 \).
Step 4: Final Answer:
The total number of ways is 120960.
Was this answer helpful?
0