Multiple choice

Fifteen students are to be placed in a queue. Out of these, 3 always stand together and out of the remaining 12, 2 do not want to stand together. Find the number of possible arrangements.

  1. P(12, 3) x 2!

  2. 12!3! x 11

  3. 12!3!2!

  4. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Treat the 3 students as one block. We have 13 items (1 block + 12 others). The 2 students who don't want to be together can be handled by total arrangements minus arrangements where they are together. The calculation results in 12! * 3! * 11.

Keep practicing — related questions