Multiple choice

In how many different ways can the letters of the word BOOKLET be arranged in such a way that B and T always come together ?

  1. 1440

  2. 720

  3. 5040

  4. 120

  5. 2520
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The word BOOKLET has 7 letters. Treating B and T as a single unit (they must always come together), we have 6 units to arrange: (BT), O, O, K, L, E. The number of arrangements is 6!/2! = 720/2 = 360 (dividing by 2! because O is repeated twice). Within the (BT) unit, B and T can be arranged in 2! = 2 ways. So total arrangements = 360 × 2 = 720.

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